diff --git a/.github/workflows/pull-compliance.yml b/.github/workflows/pull-compliance.yml
index f6720bf2f6d9d..a1b0f760c890d 100644
--- a/.github/workflows/pull-compliance.yml
+++ b/.github/workflows/pull-compliance.yml
@@ -178,6 +178,16 @@ jobs:
           GOOS: linux
           GOARCH: 386
 
+  i18n-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          check-latest: true
+      - run: make i18n-check
+
   docs:
     if: needs.files-changed.outputs.docs == 'true' || needs.files-changed.outputs.actions == 'true'
     needs: files-changed
diff --git a/Makefile b/Makefile
index 6a3fa60e495ce..df59ac98a8ff2 100644
--- a/Makefile
+++ b/Makefile
@@ -898,6 +898,16 @@ update-translations:
 	mv ./translations/*.ini ./options/locale/
 	rmdir ./translations
 
+.PHONY: i18n-backport
+i18n-backport:
+	@echo "Backport translations ..."
+	$(GO) run tools/i18n/backport.go
+
+.PHONY: i18n-check
+i18n-check:
+	@echo "Checking unused translations..."
+	$(GO) run tools/i18n/check.go
+
 .PHONY: generate-gitignore
 generate-gitignore: ## update gitignore files
 	$(GO) run build/generate-gitignores.go
diff --git a/models/actions/runner.go b/models/actions/runner.go
index 81d4249ae0b85..6e98f15f5d05a 100644
--- a/models/actions/runner.go
+++ b/models/actions/runner.go
@@ -114,6 +114,7 @@ func (r *ActionRunner) StatusName() string {
 }
 
 func (r *ActionRunner) StatusLocaleName(lang translation.Locale) string {
+	// i18n-check: actions.runners.status.*
 	return lang.TrString("actions.runners.status." + r.StatusName())
 }
 
diff --git a/models/actions/status.go b/models/actions/status.go
index 2b1d70613c71b..895fd52fb36de 100644
--- a/models/actions/status.go
+++ b/models/actions/status.go
@@ -43,6 +43,7 @@ func (s Status) String() string {
 
 // LocaleString returns the locale string name of the Status
 func (s Status) LocaleString(lang translation.Locale) string {
+	// i18n-check: actions.status.*
 	return lang.TrString("actions.status." + s.String())
 }
 
diff --git a/models/git/commit_status.go b/models/git/commit_status.go
index f85e1b15e5600..7f2f7d4030991 100644
--- a/models/git/commit_status.go
+++ b/models/git/commit_status.go
@@ -206,6 +206,7 @@ func (status *CommitStatus) APIURL(ctx context.Context) string {
 
 // LocaleString returns the locale string name of the Status
 func (status *CommitStatus) LocaleString(lang translation.Locale) string {
+	// i18n-check: repo.commitstatus.*
 	return lang.TrString("repo.commitstatus." + status.State.String())
 }
 
diff --git a/models/issues/comment.go b/models/issues/comment.go
index 9bef96d0ddfcc..9d2cdb0bfe71e 100644
--- a/models/issues/comment.go
+++ b/models/issues/comment.go
@@ -225,11 +225,13 @@ const (
 
 // LocaleString returns the locale string name of the role
 func (r RoleInRepo) LocaleString(lang translation.Locale) string {
+	// i18n-check: repo.issues.role.*
 	return lang.TrString("repo.issues.role." + string(r))
 }
 
 // LocaleHelper returns the locale tooltip of the role
 func (r RoleInRepo) LocaleHelper(lang translation.Locale) string {
+	// i18n-check: repo.issues.role.*_helper
 	return lang.TrString("repo.issues.role." + string(r) + "_helper")
 }
 
diff --git a/modules/auth/password/password.go b/modules/auth/password/password.go
index a1e101dd621cb..e0781cbf96f6e 100644
--- a/modules/auth/password/password.go
+++ b/modules/auth/password/password.go
@@ -128,6 +128,7 @@ func BuildComplexityError(locale translation.Locale) template.HTML {
 	buffer.WriteString("<ul>")
 	for _, c := range requiredList {
 		buffer.WriteString("<li>")
+		// i18n-check: form.password_*
 		buffer.WriteString(locale.TrString(c.TrNameOne))
 		buffer.WriteString("</li>")
 	}
diff --git a/modules/translation/i18n/localestore.go b/modules/translation/i18n/localestore.go
index 4f1ae7e13d2fb..2e5cc697f5fce 100644
--- a/modules/translation/i18n/localestore.go
+++ b/modules/translation/i18n/localestore.go
@@ -144,6 +144,7 @@ func (l *locale) TrHTML(trKey string, trArgs ...any) template.HTML {
 			args[i] = template.HTMLEscapeString(fmt.Sprint(v))
 		}
 	}
+	// i18n-check: ignore
 	return template.HTML(l.TrString(trKey, args...))
 }
 
diff --git a/modules/translation/translation.go b/modules/translation/translation.go
index 36ae58a9f19ad..4e985536533db 100644
--- a/modules/translation/translation.go
+++ b/modules/translation/translation.go
@@ -238,6 +238,7 @@ func (l *locale) TrN(cnt any, key1, keyN string, args ...any) template.HTML {
 	} else if t, ok := cnt.(int64); ok {
 		c = t
 	} else {
+		// i18n-check: ignore
 		return l.Tr(keyN, args...)
 	}
 
diff --git a/modules/web/middleware/binding.go b/modules/web/middleware/binding.go
index ee4eca976e367..dfaa8bca1ced4 100644
--- a/modules/web/middleware/binding.go
+++ b/modules/web/middleware/binding.go
@@ -104,8 +104,10 @@ func Validate(errs binding.Errors, data map[string]any, f Form, l translation.Lo
 
 			trName := field.Tag.Get("locale")
 			if len(trName) == 0 {
+				// i18n-check: form.*
 				trName = l.TrString("form." + field.Name)
 			} else {
+				// i18n-check: ignore
 				trName = l.TrString(trName)
 			}
 
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 80bf0801e9d52..8b7afd1ac24ac 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -49,7 +49,6 @@ webauthn_error_unable_to_process = The server could not process your request.
 webauthn_error_duplicated = The security key is not permitted for this request. Please make sure that the key is not already registered.
 webauthn_error_empty = You must set a name for this key.
 webauthn_error_timeout = Timeout reached before your key could be read. Please reload this page and retry.
-webauthn_reload = Reload
 
 repository = Repository
 organization = Organization
@@ -57,14 +56,10 @@ mirror = Mirror
 issue_milestone = Milestone
 new_repo = New Repository
 new_migrate = New Migration
-new_mirror = New Mirror
 new_fork = New Repository Fork
 new_org = New Organization
-new_project = New Project
 new_project_column = New Column
-manage_org = Manage Organizations
 admin_panel = Site Administration
-account_settings = Account Settings
 settings = Settings
 your_profile = Profile
 your_starred = Starred
@@ -368,13 +363,9 @@ config_write_file_prompt = These configuration options will be written into: %s
 [home]
 nav_menu = Navigation Menu
 uname_holder = Username or Email Address
-password_holder = Password
 switch_dashboard_context = Switch Dashboard Context
 my_repos = Repositories
-show_more_repos = Show more repositories…
-collaborative_repos = Collaborative Repositories
 my_orgs = My Organizations
-my_mirrors = My Mirrors
 view_home = View %s
 filter = Other Filters
 filter_by_team_repositories = Filter by team repositories
@@ -436,7 +427,6 @@ resent_limit_prompt = You have already requested an activation email recently. P
 has_unconfirmed_mail = Hi %s, you have an unconfirmed email address (<b>%s</b>). If you haven't received a confirmation email or need to resend a new one, please click on the button below.
 change_unconfirmed_mail_address = If your registration email address is incorrect, you can change it here and resend a new confirmation email.
 resend_mail = Click here to resend your activation email
-email_not_associate = The email address is not associated with any account.
 send_reset_mail = Send Account Recovery Email
 reset_password = Account Recovery
 invalid_code = Your confirmation code is invalid or has expired.
@@ -454,7 +444,6 @@ twofa_passcode_incorrect = Your passcode is incorrect. If you misplaced your dev
 twofa_scratch_token_incorrect = Your scratch code is incorrect.
 twofa_required = You must setup Two-Factor Authentication to get access to repositories, or try to login again.
 login_userpass = Sign In
-login_openid = OpenID
 oauth_signup_tab = Register New Account
 oauth_signup_title = Complete New Account
 oauth_signup_submit = Complete Account
@@ -482,7 +471,6 @@ authorize_application_with_scopes = With scopes: %s
 authorize_title = Authorize "%s" to access your account?
 authorization_failed = Authorization failed
 authorization_failed_desc = The authorization failed because we detected an invalid request. Please contact the maintainer of the app you have tried to authorize.
-sspi_auth_failed = SSPI authentication failed
 password_pwned = The password you chose is on a <a target="_blank" rel="noopener noreferrer" href="%s">list of stolen passwords</a> previously exposed in public data breaches. Please try again with a different password and consider changing this password elsewhere too.
 password_pwned_err = Could not complete request to HaveIBeenPwned
 last_admin = You cannot remove the last admin. There must be at least one admin.
@@ -514,8 +502,6 @@ reset_password = Recover your account
 reset_password.title = %s, you have requested to recover your account
 reset_password.text = Please click the following link to recover your account within <b>%s</b>:
 
-register_success = Registration successful
-
 issue_assigned.pull = @%[1]s assigned you to pull request %[2]s in repository %[3]s.
 issue_assigned.issue = @%[1]s assigned you to issue %[2]s in repository %[3]s.
 
@@ -560,30 +546,12 @@ yes = Yes
 no = No
 confirm = Confirm
 cancel = Cancel
-modify = Update
 
 [form]
-UserName = Username
-RepoName = Repository name
-Email = Email address
-Password = Password
-Retype = Confirm Password
-SSHTitle = SSH key name
-HttpsUrl = HTTPS URL
-PayloadUrl = Payload URL
-TeamName = Team name
-AuthName = Authorization name
-AdminEmail = Admin email
 
 NewBranchName = New branch name
-CommitSummary = Commit summary
-CommitMessage = Commit message
-CommitChoice = Commit choice
-TreeName = File path
-Content = Content
 
 SSPISeparatorReplacement = Separator
-SSPIDefaultLanguage = Default Language
 
 require_error = ` cannot be empty.`
 alpha_dash_error = ` should contain only alphanumeric, dash ('-') and underscore ('_') characters.`
@@ -608,7 +576,6 @@ username_been_taken = The username is already taken.
 username_change_not_local_user = Non-local users are not allowed to change their username.
 change_username_disabled = Changing username is disabled.
 change_full_name_disabled = Changing full name is disabled.
-username_has_not_been_changed = Username has not been changed
 repo_name_been_taken = The repository name is already used.
 repository_force_private = Force Private is enabled: private repositories cannot be made public.
 repository_files_already_exist = Files already exist for this repository. Contact the system administrator.
@@ -719,15 +686,11 @@ password = Password
 security = Security
 avatar = Avatar
 ssh_gpg_keys = SSH / GPG Keys
-social = Social Accounts
 applications = Applications
 orgs = Manage Organizations
 repos = Repositories
-delete = Delete Account
 twofa = Two-Factor Authentication (TOTP)
-account_link = Linked Accounts
 organization = Organizations
-uid = UID
 webauthn = Two-Factor Authentication (Security Keys)
 
 public_profile = Public Profile
@@ -745,10 +708,8 @@ update_language = Update Language
 update_language_not_found = Language "%s" is not available.
 update_language_success = Language has been updated.
 update_profile_success = Your profile has been updated.
-change_username = Your username has been changed.
 change_username_prompt = Note: Changing your username also changes your account URL.
 change_username_redirect_prompt = The old username will redirect until someone claims it.
-continue = Continue
 cancel = Cancel
 language = Language
 ui = Theme
@@ -776,7 +737,6 @@ keep_activity_private = Hide Activity from profile page
 keep_activity_private_popup = Makes the activity visible only for you and the admins
 
 lookup_avatar_by_mail = Look Up Avatar by Email Address
-federated_avatar_lookup = Federated Avatar Lookup
 enable_custom_avatar = Use Custom Avatar
 choose_new_avatar = Choose new avatar
 update_avatar = Update Avatar
@@ -795,7 +755,6 @@ password_incorrect = The current password is incorrect.
 change_password_success = Your password has been updated. Sign in using your new password from now on.
 password_change_disabled = Non-local users cannot update their password through the Gitea web interface.
 
-emails = Email Addresses
 manage_emails = Manage Email Addresses
 manage_themes = Select default theme
 manage_openid = Manage OpenID Addresses
@@ -840,8 +799,6 @@ principal_desc = These SSH certificate principals are associated with your accou
 gpg_desc = These public GPG keys are associated with your account. Keep your private keys safe as they allow commits to be verified.
 ssh_helper = <strong>Need help?</strong> Have a look at GitHub's guide to <a href="%s">create your own SSH keys</a> or solve <a href="%s">common problems</a> you may encounter using SSH.
 gpg_helper = <strong>Need help?</strong> Have a look at GitHub's guide <a href="%s">about GPG</a>.
-add_new_key = Add SSH Key
-add_new_gpg_key = Add GPG Key
 key_content_ssh_placeholder = Begins with 'ssh-ed25519', 'ssh-rsa', 'ecdsa-sha2-nistp256', 'ecdsa-sha2-nistp384', 'ecdsa-sha2-nistp521', 'sk-ecdsa-sha2-nistp256@openssh.com', or 'sk-ssh-ed25519@openssh.com'
 key_content_gpg_placeholder = Begins with '-----BEGIN PGP PUBLIC KEY BLOCK-----'
 add_new_principal = Add Principal
@@ -905,10 +862,6 @@ hide_openid = Hide from profile
 ssh_disabled = SSH Disabled
 ssh_signonly = SSH is currently disabled so these keys are only used for commit signature verification.
 ssh_externally_managed = This SSH key is externally managed for this user
-manage_social = Manage Associated Social Accounts
-social_desc = These social accounts can be used to sign in to your account. Make sure you recognize all of them.
-unbind = Unlink
-unbind_success = The social account has been removed successfully.
 
 manage_access_token = Manage Access Tokens
 generate_new_token = Generate New Token
@@ -919,8 +872,6 @@ generate_token_success = Your new token has been generated. Copy it now as it wi
 generate_token_name_duplicate = <strong>%s</strong> has been used as an application name already. Please use a new one.
 delete_token = Delete
 access_token_deletion = Delete Access Token
-access_token_deletion_cancel_action = Cancel
-access_token_deletion_confirm_action = Delete
 access_token_deletion_desc = Deleting a token will revoke access to your account for applications using it. This cannot be undone. Continue?
 delete_token_success = The token has been deleted. Applications using it no longer have access to your account.
 repo_and_org_access = Repository and Organization Access
@@ -939,9 +890,7 @@ permissions_list = Permissions:
 
 manage_oauth2_applications = Manage OAuth2 Applications
 edit_oauth2_application = Edit OAuth2 Application
-oauth2_applications_desc = OAuth2 applications enables your third-party application to securely authenticate users at this Gitea instance.
 remove_oauth2_application = Remove OAuth2 Application
-remove_oauth2_application_desc = Removing an OAuth2 application will revoke access to all signed access tokens. Continue?
 remove_oauth2_application_success = The application has been deleted.
 create_oauth2_application = Create a new OAuth2 Application
 create_oauth2_application_button = Create Application
@@ -956,7 +905,6 @@ oauth2_client_id = Client ID
 oauth2_client_secret = Client Secret
 oauth2_regenerate_secret = Regenerate Secret
 oauth2_regenerate_secret_hint = Lost your secret?
-oauth2_client_secret_hint = The secret will not be shown again after you leave or refresh this page. Please ensure that you have saved it.
 oauth2_application_edit = Edit
 oauth2_application_create_description = OAuth2 applications gives your third-party application access to user accounts on this instance.
 oauth2_application_remove_description = Removing an OAuth2 application will prevent it from accessing authorized user accounts on this instance. Continue?
@@ -998,7 +946,6 @@ webauthn_alternative_tip = You may want to configure an additional authenticatio
 
 manage_account_links = Manage Linked Accounts
 manage_account_links_desc = These external accounts are linked to your Gitea account.
-account_links_not_available = There are currently no external accounts linked to your Gitea account.
 link_account = Link Account
 remove_account_link = Remove Linked Account
 remove_account_link_desc = Removing a linked account will revoke its access to your Gitea account. Continue?
@@ -1042,7 +989,6 @@ repo_size = Repository Size
 template = Template
 template_select = Select a template.
 template_helper = Make repository a template
-template_description = Template repositories let users generate new repositories with the same directory structure, files, and optional settings.
 visibility = Visibility
 visibility_description = Only the owner or the organization members if they have rights, will be able to see it.
 visibility_helper = Make repository private
@@ -1065,8 +1011,6 @@ open_with_editor = Open with %s
 download_zip = Download ZIP
 download_tar = Download TAR.GZ
 download_bundle = Download BUNDLE
-generate_repo = Generate Repository
-generate_from = Generate From
 repo_desc = Description
 repo_desc_helper = Enter short description (optional)
 repo_no_desc = No description provided
@@ -1085,11 +1029,6 @@ readme = README
 readme_helper = Select a README file template.
 readme_helper_desc = This is the place where you can write a complete description for your project.
 auto_init = Initialize Repository (Adds .gitignore, License and README)
-trust_model_helper = Select trust model for signature verification. Possible options are:
-trust_model_helper_collaborator = Collaborator: Trust signatures by collaborators
-trust_model_helper_committer = Committer: Trust signatures that match committers
-trust_model_helper_collaborator_committer = Collaborator+Committer: Trust signatures by collaborators which match the committer
-trust_model_helper_default = Default: Use the default trust model for this installation
 create_repo = Create Repository
 default_branch = Default Branch
 default_branch_label = default
@@ -1108,13 +1047,11 @@ mirror_lfs = Large File Storage (LFS)
 mirror_lfs_desc = Activate mirroring of LFS data.
 mirror_lfs_endpoint = LFS Endpoint
 mirror_lfs_endpoint_desc = Sync will attempt to use the clone url to <a target="_blank" rel="noopener noreferrer" href="%s">determine the LFS server</a>. You can also specify a custom endpoint if the repository LFS data is stored somewhere else.
-mirror_last_synced = Last Synchronized
 mirror_password_placeholder = (Unchanged)
 mirror_password_blank_placeholder = (Unset)
 mirror_password_help = Change the username to erase a stored password.
 watchers = Watchers
 stargazers = Stargazers
-stars_remove_warning = This will remove all stars from this repository.
 forks = Forks
 stars = Stars
 reactions_more = and %d more
@@ -1144,7 +1081,6 @@ transfer.no_permission_to_accept = You do not have permission to accept this tra
 transfer.no_permission_to_reject = You do not have permission to reject this transfer.
 
 desc.private = Private
-desc.public = Public
 desc.public_access = Public Access
 desc.template = Template
 desc.internal = Internal
@@ -1174,7 +1110,6 @@ form.name_pattern_not_allowed = The pattern "%s" is not allowed in a repository
 
 need_auth = Authorization
 migrate_options = Migration Options
-migrate_service = Migration Service
 migrate_options_mirror_helper = This repository will be a mirror
 migrate_options_lfs = Migrate LFS files
 migrate_options_lfs_endpoint.label = LFS Endpoint
@@ -1244,8 +1179,6 @@ unstar = Unstar
 star = Star
 fork = Fork
 action.blocked_user = Cannot perform action because you are blocked by the repository owner.
-download_archive = Download Repository
-more_operations = More Operations
 
 quick_guide = Quick Guide
 clone_this_repo = Clone this repository
@@ -1259,7 +1192,6 @@ no_branch = This repository doesn’t have any branches.
 code = Code
 code.desc = Access source code, files, commits and branches.
 branch = Branch
-tree = Tree
 clear_ref = `Clear current reference`
 filter_branch_and_tag = Filter branch or tag
 find_tag = Find tag
@@ -1282,7 +1214,6 @@ release = Release
 releases = Releases
 tag = Tag
 released_this = released this
-tagged_this = tagged this
 file.title = %s at %s
 file_raw = Raw
 file_history = History
@@ -1366,7 +1297,6 @@ editor.propose_file_change = Propose file change
 editor.new_branch_name = Name the new branch for this commit
 editor.new_branch_name_desc = New branch name…
 editor.cancel = Cancel
-editor.filename_cannot_be_empty = The filename cannot be empty.
 editor.filename_is_invalid = The filename is invalid: "%s".
 editor.commit_email = Commit email
 editor.invalid_commit_email = The email for the commit is invalid.
@@ -1406,7 +1336,6 @@ editor.fork_not_editable = You have forked this repository but your fork is not
 editor.fork_failed_to_push_branch = Failed to push branch %s to your repository.
 editor.fork_branch_exists = Branch "%s" already exists in your fork, please choose a new branch name.
 
-commits.desc = Browse source code change history.
 commits.commits = Commits
 commits.no_commits = No commits in common. "%s" and "%s" have entirely different histories.
 commits.nothing_to_compare = These branches are equal.
@@ -1416,9 +1345,6 @@ commits.search_all = All Branches
 commits.author = Author
 commits.message = Message
 commits.date = Date
-commits.older = Older
-commits.newer = Newer
-commits.signed_by = Signed by
 commits.signed_by_untrusted_user = Signed by untrusted user
 commits.signed_by_untrusted_user_unmatched = Signed by untrusted user who does not match committer
 commits.gpg_key_id = GPG Key ID
@@ -1471,7 +1397,6 @@ projects.column.set_default = "Set Default"
 projects.column.set_default_desc = "Set this column as default for uncategorized issues and pulls"
 projects.column.delete = "Delete Column"
 projects.column.deletion_desc = "Deleting a project column moves all related issues to the default column. Continue?"
-projects.column.color = "Color"
 projects.open = Open
 projects.close = Close
 projects.column.assigned_to = Assigned to
@@ -1520,8 +1445,6 @@ issues.create = Create Issue
 issues.new_label = New Label
 issues.new_label_placeholder = Label name
 issues.new_label_desc_placeholder = Description
-issues.create_label = Create Label
-issues.label_templates.title = Load a predefined set of labels
 issues.label_templates.info = No labels exist yet. Create a label with 'New Label' or use a predefined label set:
 issues.label_templates.helper = Select a label set
 issues.label_templates.use = Use Label Set
@@ -1633,8 +1556,6 @@ issues.ref_issue_from = `<a href="%[3]s">referenced this issue %[4]s</a> <a id="
 issues.ref_pull_from = `<a href="%[3]s">referenced this pull request %[4]s</a> <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 issues.ref_closing_from = `<a href="%[3]s">referenced a pull request %[4]s that will close this issue</a> <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 issues.ref_reopening_from = `<a href="%[3]s">referenced a pull request %[4]s that will reopen this issue</a> <a id="%[1]s" href="#%[1]s">%[2]s</a>`
-issues.ref_closed_from = `<a href="%[3]s">closed this issue %[4]s</a> <a id="%[1]s" href="#%[1]s">%[2]s</a>`
-issues.ref_reopened_from = `<a href="%[3]s">reopened this issue %[4]s</a> <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 issues.ref_from = `from %[1]s`
 issues.author = Author
 issues.author_helper = This user is the author.
@@ -1684,7 +1605,6 @@ issues.label.filter_sort.by_size = Smallest size
 issues.label.filter_sort.reverse_by_size = Largest size
 issues.num_participants = %d Participants
 issues.attachment.open_tab = `Click to see "%s" in a new tab`
-issues.attachment.download = `Click to download "%s"`
 issues.subscribe = Subscribe
 issues.unsubscribe = Unsubscribe
 issues.unpin = Unpin
@@ -1740,28 +1660,21 @@ issues.add_time_manually = Manually Add Time
 issues.add_time_hours = Hours
 issues.add_time_minutes = Minutes
 issues.add_time_sum_to_small = No time was entered.
-issues.time_spent_total = Total Time Spent
 issues.time_spent_from_all_authors = `Total Time Spent: %s`
 
 issues.due_date = Due Date
-issues.invalid_due_date_format = "Due date format must be 'yyyy-mm-dd'."
-issues.error_modifying_due_date = "Failed to modify the due date."
-issues.error_removing_due_date = "Failed to remove the due date."
 issues.push_commit_1 = "added %d commit %s"
 issues.push_commits_n = "added %d commits %s"
 issues.force_push_codes = `force-pushed %[1]s from <a class="ui sha" href="%[3]s"><code>%[2]s</code></a> to <a class="ui sha" href="%[5]s"><code>%[4]s</code></a> %[6]s`
 issues.force_push_compare = Compare
 issues.due_date_form = "yyyy-mm-dd"
-issues.due_date_form_add = "Add due date"
 issues.due_date_form_edit = "Edit"
 issues.due_date_form_remove = "Remove"
-issues.due_date_not_writer = "You need write access to this repository in order to update the due date of an issue."
 issues.due_date_not_set = "No due date set."
 issues.due_date_added = "added the due date %s %s"
 issues.due_date_modified = "modified the due date from %[2]s to %[1]s %[3]s"
 issues.due_date_remove = "removed the due date %s %s"
 issues.due_date_overdue = "Overdue"
-issues.due_date_invalid = "The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'."
 issues.dependency.title = Dependencies
 issues.dependency.issue_no_dependencies = No dependencies set.
 issues.dependency.pr_no_dependencies = No dependencies set.
@@ -1802,7 +1715,6 @@ issues.review.dismissed_label = Dismissed
 issues.review.left_comment = left a comment
 issues.review.content.empty = You need to leave a comment indicating the requested change(s).
 issues.review.reject = "requested changes %s"
-issues.review.wait = "was requested for review %s"
 issues.review.add_review_request = "requested review from %s %s"
 issues.review.remove_review_request = "removed review request for %s %s"
 issues.review.remove_review_request_self = "refused to review %s"
@@ -1827,7 +1739,6 @@ issues.review.requested = Review pending
 issues.review.rejected = Changes requested
 issues.review.stale = Updated since approval
 issues.review.unofficial = Uncounted approval
-issues.assignee.error = Not all assignees was added due to an unexpected error.
 issues.reference_issue.body = Body
 issues.content_history.deleted = deleted
 issues.content_history.edited = edited
@@ -2151,7 +2062,6 @@ contributors.contribution_type.additions = Additions
 contributors.contribution_type.deletions = Deletions
 
 settings = Settings
-settings.desc = Settings is where you can manage the settings for the repository
 settings.options = Repository
 settings.public_access = Public Access
 settings.public_access_desc = Configure public visitor's access permissions to override the defaults of this repository.
@@ -2181,7 +2091,6 @@ settings.mirror_settings.docs.pull_mirror_instructions = To set up a pull mirror
 settings.mirror_settings.docs.more_information_if_disabled = You can find out more about push and pull mirrors here:
 settings.mirror_settings.docs.doc_link_title = How do I mirror repositories?
 settings.mirror_settings.docs.doc_link_pull_section = the "Pulling from a remote repository" section of the documentation.
-settings.mirror_settings.docs.pulling_remote_title = Pulling from a remote repository
 settings.mirror_settings.mirrored_repository = Mirrored repository
 settings.mirror_settings.pushed_repository = Pushed repository
 settings.mirror_settings.direction = Direction
@@ -2285,13 +2194,10 @@ settings.signing_settings = Signing Verification Settings
 settings.trust_model = Signature Trust Model
 settings.trust_model.default = Default Trust Model
 settings.trust_model.default.desc= Use the default repository trust model for this installation.
-settings.trust_model.collaborator = Collaborator
 settings.trust_model.collaborator.long = Collaborator: Trust signatures by collaborators
 settings.trust_model.collaborator.desc = Valid signatures by collaborators of this repository will be marked "trusted" - (whether they match the committer or not). Otherwise, valid signatures will be marked "untrusted" if the signature matches the committer and "unmatched" if not.
-settings.trust_model.committer = Committer
 settings.trust_model.committer.long = Committer: Trust signatures that match committers (This matches GitHub and will force Gitea signed commits to have Gitea as the committer)
 settings.trust_model.committer.desc = Valid signatures will only be marked "trusted" if they match the committer, otherwise they will be marked "unmatched". This forces Gitea to be the committer on signed commits with the actual committer marked as Co-authored-by: and Co-committed-by: trailer in the commit. The default Gitea key must match a User in the database.
-settings.trust_model.collaboratorcommitter = Collaborator+Committer
 settings.trust_model.collaboratorcommitter.long = Collaborator+Committer: Trust signatures by collaborators which match the committer
 settings.trust_model.collaboratorcommitter.desc = Valid signatures by collaborators of this repository will be marked "trusted" if they match the committer. Otherwise, valid signatures will be marked "untrusted" if the signature matches the committer and "unmatched" otherwise. This will force Gitea to be marked as the committer on signed commits with the actual committer marked as Co-Authored-By: and Co-Committed-By: trailer in the commit. The default Gitea key must match a User in the database.
 settings.wiki_delete = Delete Wiki Data
@@ -2350,7 +2256,6 @@ settings.githook_edit_desc = If the hook is inactive, sample content will be pre
 settings.githook_name = Hook Name
 settings.githook_content = Hook Content
 settings.update_githook = Update Hook
-settings.add_webhook_desc = Gitea will send <code>POST</code> requests with a specified content type to the target URL. Read more in the <a target="_blank" rel="noopener noreferrer" href="%s">webhooks guide</a>.
 settings.payload_url = Target URL
 settings.http_method = HTTP Method
 settings.content_type = POST Content Type
@@ -2430,9 +2335,6 @@ settings.update_webhook = Update Webhook
 settings.update_hook_success = The webhook has been updated.
 settings.delete_webhook = Remove Webhook
 settings.recent_deliveries = Recent Deliveries
-settings.hook_type = Hook Type
-settings.slack_token = Token
-settings.slack_domain = Domain
 settings.slack_channel = Channel
 settings.add_web_hook_desc = Integrate <a target="_blank" rel="noreferrer" href="%s">%s</a> into your repository.
 settings.web_hook_name_gitea = Gitea
@@ -2469,12 +2371,7 @@ settings.branches = Branches
 settings.protected_branch = Branch Protection
 settings.protected_branch.save_rule = Save Rule
 settings.protected_branch.delete_rule = Delete Rule
-settings.protected_branch_can_push = Allow push?
-settings.protected_branch_can_push_yes = You can push
-settings.protected_branch_can_push_no = You cannot push
 settings.branch_protection = Branch Protection Rules for Branch '<b>%s</b>'
-settings.protect_this_branch = Enable Branch Protection
-settings.protect_this_branch_desc = Prevents deletion and restricts Git pushing and merging to the branch.
 settings.protect_disable_push = Disable Push
 settings.protect_disable_push_desc = No pushing will be allowed to this branch.
 settings.protect_disable_force_push = Disable Force Push
@@ -2526,8 +2423,6 @@ settings.protect_protected_file_patterns = "Protected file patterns (separated u
 settings.protect_protected_file_patterns_desc = "Protected files are not allowed to be changed directly even if user has rights to add, edit, or delete files in this branch. Multiple patterns can be separated using semicolon (';'). See <a href='%[1]s'>%[2]s</a> documentation for pattern syntax. Examples: <code>.drone.yml</code>, <code>/docs/**/*.txt</code>."
 settings.protect_unprotected_file_patterns = "Unprotected file patterns (separated using semicolon ';'):"
 settings.protect_unprotected_file_patterns_desc = "Unprotected files that are allowed to be changed directly if user has write access, bypassing push restriction. Multiple patterns can be separated using semicolon (';'). See <a href='%[1]s'>%[2]s</a> documentation for pattern syntax. Examples: <code>.drone.yml</code>, <code>/docs/**/*.txt</code>."
-settings.add_protected_branch = Enable protection
-settings.delete_protected_branch = Disable protection
 settings.update_protect_branch_success = Branch protection for rule "%s" has been updated.
 settings.remove_protected_branch_success = Branch protection for rule "%s" has been removed.
 settings.remove_protected_branch_failed = Removing branch protection rule "%s" failed.
@@ -2544,7 +2439,6 @@ settings.block_admin_merge_override_desc = Administrators must follow branch pro
 settings.default_branch_desc = Select a default repository branch for pull requests and code commits:
 settings.merge_style_desc = Merge Styles
 settings.default_merge_style_desc = Default Merge Style
-settings.choose_branch = Choose a branch…
 settings.no_protected_branch = There are no protected branches.
 settings.edit_protected_branch = Edit
 settings.protected_branch_required_rule_name = Required rule name
@@ -2621,8 +2515,6 @@ settings.lfs_pointers.associateAccessible=Associate accessible %d OIDs
 settings.rename_branch_failed_exist=Cannot rename branch because target branch %s exists.
 settings.rename_branch_failed_not_exist=Cannot rename branch %s because it does not exist.
 settings.rename_branch_success =Branch %s was successfully renamed to %s.
-settings.rename_branch_from=old branch name
-settings.rename_branch_to=new branch name
 settings.rename_branch=Rename branch
 
 diff.browse_source = Browse Source
@@ -2676,7 +2568,6 @@ diff.protected = Protected
 diff.image.side_by_side = Side by Side
 diff.image.swipe = Swipe
 diff.image.overlay = Overlay
-diff.has_escaped = This line has hidden Unicode characters
 diff.show_file_tree = Show file tree
 diff.hide_file_tree = Hide file tree
 diff.submodule_added = Submodule %[1]s added at %[2]s
@@ -2696,7 +2587,6 @@ release.compare = Compare
 release.edit = edit
 release.ahead.commits = <strong>%d</strong> commits
 release.ahead.target = to %s since this release
-tag.ahead.target = to %s since this tag
 release.source_code = Source Code
 release.new_subheader = Releases organize project versions.
 release.edit_subheader = Releases organize project versions.
@@ -2724,7 +2614,6 @@ release.deletion_tag_success = The tag has been deleted.
 release.tag_name_already_exist = A release with this tag name already exists.
 release.tag_name_invalid = The tag name is not valid.
 release.tag_name_protected = The tag name is protected.
-release.tag_already_exist = This tag name already exists.
 release.downloads = Downloads
 release.download_count = Downloads: %s
 release.add_tag_msg = Use the title and content of release as tag message.
@@ -2734,7 +2623,6 @@ release.tags_for = Tags for %s
 
 branch.name = Branch Name
 branch.already_exists = A branch named "%s" already exists.
-branch.delete_head = Delete
 branch.delete = Delete Branch "%s"
 branch.delete_html = Delete Branch
 branch.delete_desc = Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?
@@ -2762,7 +2650,6 @@ branch.create_new_branch = Create branch from branch:
 branch.confirm_create_branch = Create branch
 branch.warning_rename_default_branch = You are renaming the default branch.
 branch.rename_branch_to = Rename "%s" to:
-branch.confirm_rename_branch = Rename branch
 branch.create_branch_operation = Create branch
 branch.new_branch = Create new branch
 branch.new_branch_from = Create new branch from "%s"
@@ -2778,7 +2665,6 @@ tag.create_tag_from = Create new tag from "%s"
 tag.create_success = Tag "%s" has been created.
 
 topic.manage_topics = Manage Topics
-topic.done = Done
 topic.count_prompt = You cannot select more than 25 topics
 topic.format_prompt = Topics must start with a letter or number, can include dashes ('-') and dots ('.'), can be up to 35 characters long. Letters must be lowercase.
 
@@ -2829,7 +2715,6 @@ form.create_org_not_allowed = You are not allowed to create an organization.
 
 settings = Settings
 settings.options = Organization
-settings.full_name = Full Name
 settings.email = Contact Email
 settings.website = Website
 settings.location = Location
@@ -2867,11 +2752,8 @@ settings.confirm_delete_account = Confirm Deletion
 settings.delete_failed = Delete Organization failed because of internal error
 settings.delete_successful = Organization <b>%s</b> has been deleted successfully.
 settings.hooks_desc = Add webhooks which will be triggered for <strong>all repositories</strong> under this organization.
-
 settings.labels_desc = Add labels which can be used on issues for <strong>all repositories</strong> under this organization.
 
-members.membership_visibility = Membership Visibility:
-members.public = Visible
 members.public_helper = make hidden
 members.private = Hidden
 members.private_helper = make visible
@@ -2882,8 +2764,6 @@ members.remove = Remove
 members.remove.detail = Remove %[1]s from %[2]s?
 members.leave = Leave
 members.leave.detail = Leave %s?
-members.invite_desc = Add a new member to %s:
-members.invite_now = Invite Now
 
 teams.join = Join
 teams.leave = Leave
@@ -2903,7 +2783,6 @@ teams.admin_access_helper = Members can pull and push to team repositories and a
 teams.no_desc = This team has no description
 teams.settings = Settings
 teams.owners_permission_desc = Owners have full access to <strong>all repositories</strong> and have <strong>administrator access</strong> to the organization.
-teams.members = Team Members
 teams.update_settings = Update Settings
 teams.delete_team = Delete Team
 teams.add_team_member = Add Team Member
@@ -2912,14 +2791,9 @@ teams.invite_team_member.list = Pending Invitations
 teams.delete_team_title = Delete Team
 teams.delete_team_desc = Deleting a team revokes repository access from its members. Continue?
 teams.delete_team_success = The team has been deleted.
-teams.read_permission_desc = This team grants <strong>Read</strong> access: members can view and clone team repositories.
 teams.write_permission_desc = This team grants <strong>Write</strong> access: members can read from and push to team repositories.
 teams.admin_permission_desc = This team grants <strong>Admin</strong> access: members can read from, push to and add collaborators to team repositories.
-teams.create_repo_permission_desc = Additionally, this team grants <strong>Create repository</strong> permission: members can create new repositories in organization.
-teams.repositories = Team Repositories
-teams.remove_all_repos_title = Remove all team repositories
 teams.remove_all_repos_desc = This will remove all repositories from the team.
-teams.add_all_repos_title = Add all repositories
 teams.add_all_repos_desc = This will add all the organization's repositories to the team.
 teams.add_nonexistent_repo = "The repository you're trying to add doesn't exist, please create it first."
 teams.add_duplicate_users = User is already a team member.
@@ -2930,9 +2804,6 @@ teams.specific_repositories = Specific repositories
 teams.specific_repositories_helper = Members will only have access to repositories explicitly added to the team. Selecting this <strong>will not</strong> automatically remove repositories already added with <i>All repositories</i>.
 teams.all_repositories = All repositories
 teams.all_repositories_helper = Team has access to all repositories. Selecting this will <strong>add all existing</strong> repositories to the team.
-teams.all_repositories_read_permission_desc = This team grants <strong>Read</strong> access to <strong>all repositories</strong>: members can view and clone repositories.
-teams.all_repositories_write_permission_desc = This team grants <strong>Write</strong> access to <strong>all repositories</strong>: members can read from and push to repositories.
-teams.all_repositories_admin_permission_desc = This team grants <strong>Admin</strong> access to <strong>all repositories</strong>: members can read from, push to and add collaborators to repositories.
 teams.invite.title = You have been invited to join team <strong>%s</strong> in organization <strong>%s</strong>.
 teams.invite.by = Invited by %s
 teams.invite.description = Please click the button below to join the team.
@@ -3146,7 +3017,6 @@ repos.unadopted = Unadopted Repositories
 repos.unadopted.no_more = No more unadopted repositories found
 repos.owner = Owner
 repos.name = Name
-repos.private = Private
 repos.issues = Issues
 repos.size = Size
 repos.lfs_size = LFS Size
@@ -3185,7 +3055,6 @@ auths.updated = Updated
 auths.auth_type = Authentication Type
 auths.auth_name = Authentication Name
 auths.security_protocol = Security Protocol
-auths.domain = Domain
 auths.host = Host
 auths.port = Port
 auths.bind_dn = Bind DN
@@ -3214,7 +3083,6 @@ auths.user_attribute_in_group = User Attribute Listed In Group
 auths.map_group_to_team = Map LDAP groups to Organization teams (leave the field empty to skip)
 auths.map_group_to_team_removal = Remove users from synchronized teams if user does not belong to corresponding LDAP group
 auths.enable_ldap_groups = Enable LDAP groups
-auths.ms_ad_sa = MS AD Search Attributes
 auths.smtp_auth = SMTP Authentication Type
 auths.smtphost = SMTP Host
 auths.smtpport = SMTP Port
@@ -3251,7 +3119,6 @@ auths.oauth2_admin_group = Group Claim value for administrator users. (Optional
 auths.oauth2_restricted_group = Group Claim value for restricted users. (Optional - requires claim name above)
 auths.oauth2_map_group_to_team = Map claimed groups to Organization teams. (Optional - requires claim name above)
 auths.oauth2_map_group_to_team_removal = Remove users from synchronized teams if user does not belong to corresponding group.
-auths.enable_auto_register = Enable Auto Registration
 auths.sspi_auto_create_users = Automatically create users
 auths.sspi_auto_create_users_helper = Allow SSPI auth method to automatically create new accounts for users that login for the first time
 auths.sspi_auto_activate_users = Automatically activate users
@@ -3308,7 +3175,6 @@ config.run_mode = Run Mode
 config.git_version = Git Version
 config.app_data_path = App Data Path
 config.repo_root_path = Repository Root Path
-config.lfs_root_path = LFS Root Path
 config.log_file_root_path = Log Path
 config.script_type = Script Type
 config.reverse_auth_user = Reverse Authentication User
@@ -3383,9 +3249,6 @@ config.send_test_mail_submit = Send
 config.test_mail_failed = Failed to send a testing email to "%s": %v
 config.test_mail_sent = A testing email has been sent to "%s".
 
-config.oauth_config = OAuth Configuration
-config.oauth_enabled = Enabled
-
 config.cache_config = Cache Configuration
 config.cache_adapter = Cache Adapter
 config.cache_interval = Cache Interval
@@ -3403,10 +3266,8 @@ config.cookie_name = Cookie Name
 config.gc_interval_time = GC Interval Time
 config.session_life_time = Session Life Time
 config.https_only = HTTPS Only
-config.cookie_life_time = Cookie Life Time
 
 config.picture_config = Picture and Avatar Configuration
-config.picture_service = Picture Service
 config.disable_gravatar = Disable Gravatar
 config.enable_federated_avatar = Enable Federated Avatars
 config.open_with_editor_app_help = The "Open with" editors for the clone menu. If left empty, the default will be used. Expand to see the default.
@@ -3426,7 +3287,6 @@ config.git_gc_timeout = GC Operation Timeout
 config.log_config = Log Configuration
 config.logger_name_fmt = Logger: %s
 config.disabled_logger = Disabled
-config.access_log_mode = Access Log Mode
 config.access_log_template = Access Log Template
 config.xorm_log_sql = Log SQL
 
@@ -3446,13 +3306,9 @@ monitor.trace = Trace
 monitor.performance_logs = Performance Logs
 monitor.processes_count = %d Processes
 monitor.download_diagnosis_report = Download diagnosis report
-monitor.desc = Description
-monitor.start = Start Time
-monitor.execute_time = Execution Time
 monitor.last_execution_result = Result
 monitor.process.cancel = Cancel process
 monitor.process.cancel_desc = Cancelling a process may cause data loss
-monitor.process.children = Children
 
 monitor.queues = Queues
 monitor.queue = Queue: %s
@@ -3572,7 +3428,6 @@ watching = Watching
 no_subscriptions = No subscriptions
 
 [gpg]
-default_key=Signed with default key
 error.extract_sign = Failed to extract signature
 error.generate_hash = Failed to generate hash of commit
 error.no_committer_account = No account linked to committer's email address
@@ -3585,7 +3440,6 @@ error.probable_bad_default_signature = "WARNING! Although the default key has th
 [units]
 unit = Unit
 error.no_unit_allowed_repo = You are not allowed to access any section of this repository.
-error.unit_not_allowed = You are not allowed to access this repository section.
 
 [packages]
 title = Packages
@@ -3640,7 +3494,6 @@ composer.registry = Setup this registry in your <code>~/.composer/config.json</c
 composer.install = To install the package using Composer, run the following command:
 composer.dependencies = Dependencies
 composer.dependencies.development = Development Dependencies
-conan.details.repository = Repository
 conan.registry = Setup this registry from the command line:
 conan.install = To install the package using Conan, run the following command:
 conda.registry = Setup this registry as a Conda repository in your <code>.condarc</code> file:
@@ -3731,7 +3584,6 @@ owner.settings.cleanuprules.none = No cleanup rules available. Please consult th
 owner.settings.cleanuprules.preview = Cleanup Rule Preview
 owner.settings.cleanuprules.preview.overview = %d packages are scheduled to be removed.
 owner.settings.cleanuprules.preview.none = Cleanup rule does not match any packages.
-owner.settings.cleanuprules.enabled = Enabled
 owner.settings.cleanuprules.pattern_full_match = Apply pattern to full package name
 owner.settings.cleanuprules.keep.title = Versions that match these rules are kept, even if they match a removal rule below.
 owner.settings.cleanuprules.keep.count = Keep the most recent
@@ -3868,7 +3720,6 @@ variables.none = There are no variables yet.
 variables.deletion = Remove variable
 variables.deletion.description = Removing a variable is permanent and cannot be undone. Continue?
 variables.description = Variables will be passed to certain actions and cannot be read otherwise.
-variables.id_not_exist = Variable with ID %d does not exist.
 variables.edit = Edit Variable
 variables.deletion.failed = Failed to remove variable.
 variables.deletion.success = The variable has been removed.
diff --git a/routers/web/admin/admin.go b/routers/web/admin/admin.go
index 0cd13acf6012b..efa6c67d88d94 100644
--- a/routers/web/admin/admin.go
+++ b/routers/web/admin/admin.go
@@ -180,6 +180,7 @@ func DashboardPost(ctx *context.Context) {
 			task := cron.GetTask(form.Op)
 			if task != nil {
 				go task.RunWithUser(ctx.Doer, nil)
+				// i18n-check: admin.dashboard.*
 				ctx.Flash.Success(ctx.Tr("admin.dashboard.task.started", ctx.Tr("admin.dashboard."+form.Op)))
 			} else {
 				ctx.Flash.Error(ctx.Tr("admin.dashboard.task.unknown", form.Op))
diff --git a/routers/web/repo/actions/view.go b/routers/web/repo/actions/view.go
index 7e1b923fa4b05..f19cbf1b9cb87 100644
--- a/routers/web/repo/actions/view.go
+++ b/routers/web/repo/actions/view.go
@@ -847,6 +847,7 @@ func Run(ctx *context_module.Context) {
 	})
 	if err != nil {
 		if errLocale := util.ErrorAsLocale(err); errLocale != nil {
+			// i18n-check: ignore
 			ctx.Flash.Error(ctx.Tr(errLocale.TrKey, errLocale.TrArgs...))
 			ctx.Redirect(redirectURL)
 		} else {
diff --git a/routers/web/repo/activity.go b/routers/web/repo/activity.go
index 8232f0cc04bc3..0a883e774acbd 100644
--- a/routers/web/repo/activity.go
+++ b/routers/web/repo/activity.go
@@ -51,6 +51,7 @@ func Activity(ctx *context.Context) {
 	}
 	ctx.Data["DateFrom"] = timeFrom
 	ctx.Data["DateUntil"] = timeUntil
+	// i18n-check: repo.activity.period.*
 	ctx.Data["PeriodText"] = ctx.Tr("repo.activity.period." + ctx.Data["Period"].(string))
 
 	canReadCode := ctx.Repo.CanRead(unit.TypeCode)
diff --git a/routers/web/repo/editor_error.go b/routers/web/repo/editor_error.go
index 245226a039e4d..04904a178157a 100644
--- a/routers/web/repo/editor_error.go
+++ b/routers/web/repo/editor_error.go
@@ -39,6 +39,7 @@ func editorHandleFileOperationErrorRender(ctx *context_service.Context, message,
 
 func editorHandleFileOperationError(ctx *context_service.Context, targetBranchName string, err error) {
 	if errAs := util.ErrorAsLocale(err); errAs != nil {
+		// i18n-check: ignore
 		ctx.JSONError(ctx.Tr(errAs.TrKey, errAs.TrArgs...))
 	} else if errAs, ok := errorAs[git.ErrNotExist](err); ok {
 		ctx.JSONError(ctx.Tr("repo.editor.file_modifying_no_longer_exists", errAs.RelPath))
diff --git a/routers/web/repo/migrate.go b/routers/web/repo/migrate.go
index ea15e90e5c297..9b3e52191aea4 100644
--- a/routers/web/repo/migrate.go
+++ b/routers/web/repo/migrate.go
@@ -314,10 +314,11 @@ func MigrateStatus(ctx *context.Context) {
 		var translatableMessage admin_model.TranslatableMessage
 		if err := json.Unmarshal([]byte(message), &translatableMessage); err != nil {
 			translatableMessage = admin_model.TranslatableMessage{
-				Format: "migrate.migrating_failed.error",
+				Format: "repo.migrate.migrating_failed.error",
 				Args:   []any{task.Message},
 			}
 		}
+		// i18n-check: repo.migrate.migrating_failed.*
 		message = ctx.Locale.TrString(translatableMessage.Format, translatableMessage.Args...)
 	}
 
diff --git a/routers/web/user/setting/profile.go b/routers/web/user/setting/profile.go
index 98995cd69c435..622c897cc8b6c 100644
--- a/routers/web/user/setting/profile.go
+++ b/routers/web/user/setting/profile.go
@@ -71,7 +71,7 @@ func ProfilePost(ctx *context.Context) {
 
 	if form.Name != "" {
 		if user_model.IsFeatureDisabledWithLoginType(ctx.Doer, setting.UserFeatureChangeUsername) {
-			ctx.Flash.Error(ctx.Tr("user.form.change_username_disabled"))
+			ctx.Flash.Error(ctx.Tr("form.change_username_disabled"))
 			ctx.Redirect(setting.AppSubURL + "/user/settings")
 			return
 		}
@@ -107,7 +107,7 @@ func ProfilePost(ctx *context.Context) {
 
 	if form.FullName != "" {
 		if user_model.IsFeatureDisabledWithLoginType(ctx.Doer, setting.UserFeatureChangeFullName) {
-			ctx.Flash.Error(ctx.Tr("user.form.change_full_name_disabled"))
+			ctx.Flash.Error(ctx.Tr("form.change_full_name_disabled"))
 			ctx.Redirect(setting.AppSubURL + "/user/settings")
 			return
 		}
diff --git a/services/context/base.go b/services/context/base.go
index f3f92b7eeb906..a302658bc9828 100644
--- a/services/context/base.go
+++ b/services/context/base.go
@@ -167,6 +167,7 @@ func (b *Base) ServeContent(r io.ReadSeeker, opts *ServeHeaderOptions) {
 }
 
 func (b *Base) Tr(msg string, args ...any) template.HTML {
+	// i18n-check: ignore
 	return b.Locale.Tr(msg, args...)
 }
 
diff --git a/services/cron/setting.go b/services/cron/setting.go
index 6dad88830abb5..09fac9166293b 100644
--- a/services/cron/setting.go
+++ b/services/cron/setting.go
@@ -70,6 +70,7 @@ func (b *BaseConfig) DoNoticeOnSuccess() bool {
 // Please note the `status` string will be concatenated with `admin.dashboard.cron.` and `admin.dashboard.task.` to provide locale messages. Similarly `name` will be composed with `admin.dashboard.` to provide the locale name for the task.
 func (b *BaseConfig) FormatMessage(locale translation.Locale, name, status, doer string, args ...any) string {
 	realArgs := make([]any, 0, len(args)+2)
+	// i18n-check: admin.dashboard.*
 	realArgs = append(realArgs, locale.TrString("admin.dashboard."+name))
 	if doer == "" {
 		realArgs = append(realArgs, "(Cron)")
@@ -80,7 +81,9 @@ func (b *BaseConfig) FormatMessage(locale translation.Locale, name, status, doer
 		realArgs = append(realArgs, args...)
 	}
 	if doer == "" {
+		// i18n-check: admin.dashboard.cron.*
 		return locale.TrString("admin.dashboard.cron."+status, realArgs...)
 	}
+	// i18n-check: admin.dashboard.task.*
 	return locale.TrString("admin.dashboard.task."+status, realArgs...)
 }
diff --git a/services/cron/tasks.go b/services/cron/tasks.go
index f8a7444c49e5c..6e29b5fbb6b89 100644
--- a/services/cron/tasks.go
+++ b/services/cron/tasks.go
@@ -159,6 +159,7 @@ func RegisterTask(name string, config Config, fun func(context.Context, *user_mo
 	log.Debug("Registering task: %s", name)
 
 	i18nKey := "admin.dashboard." + name
+	// i18n-check: admin.dashboard.*
 	if value := translation.NewLocale("en-US").TrString(i18nKey); value == i18nKey {
 		return fmt.Errorf("translation is missing for task %q, please add translation for %q", name, i18nKey)
 	}
diff --git a/build/backport-locales.go b/tools/i18n/backport.go
similarity index 100%
rename from build/backport-locales.go
rename to tools/i18n/backport.go
diff --git a/tools/i18n/check.go b/tools/i18n/check.go
new file mode 100644
index 0000000000000..33de999fb0ab5
--- /dev/null
+++ b/tools/i18n/check.go
@@ -0,0 +1,301 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build ignore
+
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"text/template"
+	"text/template/parse"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/templates"
+
+	"github.com/gobwas/glob"
+)
+
+func searchTranslationKeyInDirs(keys []string) ([]bool, []string, error) {
+	res := make([]bool, len(keys))
+	untranslatedKeysSum := make([]string, 0, 20)
+	for _, dir := range []string{
+		"cmd",
+		"models",
+		"modules",
+		"routers",
+		"services",
+		"templates",
+	} {
+		untranslatedKeys, err := checkTranslationKeysInDir(dir, keys, &res)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		untranslatedKeysSum = append(untranslatedKeysSum, untranslatedKeys...)
+	}
+	return res, untranslatedKeysSum, nil
+}
+
+func checkTranslationKeysInDir(dir string, keys []string, res *[]bool) ([]string, error) {
+	var untranslatedSum []string
+	if err := filepath.WalkDir(dir, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() ||
+			(!strings.HasSuffix(d.Name(), ".go") && !strings.HasSuffix(d.Name(), ".tmpl")) ||
+			strings.HasSuffix(d.Name(), "_test.go") { // don't search in test files
+			return nil
+		}
+
+		// search unused keys in the file
+		if err := searchUnusedKeyInFile(dir, path, keys, res); err != nil {
+			return err
+		}
+
+		// search untranslated keys in the file
+		untranslated, err := searchUnTranslatedKeyInFile(dir, path, keys)
+		if err != nil {
+			return err
+		}
+		untranslatedSum = append(untranslatedSum, untranslated...)
+
+		return nil
+	}); err != nil {
+		return nil, err
+	}
+	return untranslatedSum, nil
+}
+
+func searchUnusedKeyInFile(dir, path string, keys []string, res *[]bool) error {
+	bs, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	for i, key := range keys {
+		if !(*res)[i] && strings.Contains(string(bs), `"`+key+`"`) {
+			(*res)[i] = true
+		}
+	}
+	return nil
+}
+
+func searchUntranslatedKeyInCall(path string, fset *token.FileSet, astf *ast.File, call *ast.CallExpr, arg ast.Expr, keys []string) string {
+	if lit, ok := arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
+		key := strings.Trim(lit.Value, `"`)
+		if !slices.Contains(keys, key) {
+			return key
+		}
+		return ""
+	}
+
+	var lastCg *ast.CommentGroup
+	for _, cg := range astf.Comments {
+		if cg.End() < call.Pos() {
+			if lastCg == nil || cg.End() > lastCg.End() {
+				lastCg = cg
+			}
+		}
+	}
+	if lastCg == nil {
+		fmt.Printf("no comment found for a dynamic translation key: %s:%d\n", path, fset.Position(call.Pos()).Line)
+		os.Exit(1)
+		return ""
+	}
+
+	transKeyMatch, ok := strings.CutPrefix(lastCg.Text(), "i18n-check:")
+	if !ok {
+		fmt.Printf("no comment found for a dynamic translation key: %s:%d\n", path, fset.Position(call.Pos()).Line)
+		os.Exit(1)
+		return ""
+	}
+	transKeyMatch = strings.TrimSpace(transKeyMatch)
+	switch transKeyMatch {
+	case "ignore": // i18n-check: ignore
+		return ""
+	default: // i18n-check: <transKeyMatch>
+		g := glob.MustCompile(transKeyMatch)
+		found := false
+		for _, key := range keys {
+			if g.Match(key) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			return transKeyMatch
+		}
+	}
+	return ""
+}
+
+func searchUntranslatedKeyInGoFile(dir, path string, keys []string) ([]string, error) {
+	if filepath.Ext(path) != ".go" || strings.HasSuffix(path, "_test.go") {
+		return nil, nil
+	}
+
+	var untranslated []string
+	fs := token.NewFileSet()
+	node, err := parser.ParseFile(fs, path, nil, parser.ParseComments)
+	if err != nil {
+		return nil, err
+	}
+
+	ast.Inspect(node, func(n ast.Node) bool {
+		call, ok := n.(*ast.CallExpr)
+		if !ok {
+			return true
+		}
+		if funIdent, ok := call.Fun.(*ast.SelectorExpr); ok {
+			switch funIdent.Sel.Name {
+			case "Tr", "TrString":
+				if len(call.Args) >= 1 {
+					if key := searchUntranslatedKeyInCall(path, fs, node, call, call.Args[0], keys); key != "" {
+						untranslated = append(untranslated, key)
+					}
+				}
+			case "TrN":
+				if len(call.Args) >= 3 {
+					if key := searchUntranslatedKeyInCall(path, fs, node, call, call.Args[1], keys); key != "" {
+						untranslated = append(untranslated, key)
+					}
+					if key := searchUntranslatedKeyInCall(path, fs, node, call, call.Args[2], keys); key != "" {
+						untranslated = append(untranslated, key)
+					}
+				}
+			}
+		}
+		return true
+	})
+
+	return untranslated, err
+}
+
+func extractI18nKeys(node parse.Node) []string {
+	switch n := node.(type) {
+	case *parse.ListNode:
+		var keys []string
+		for _, sub := range n.Nodes {
+			keys = append(keys, extractI18nKeys(sub)...)
+		}
+		return keys
+	case *parse.ActionNode:
+		return extractI18nKeys(n.Pipe)
+	case *parse.PipeNode:
+		var keys []string
+		for _, cmd := range n.Cmds {
+			keys = append(keys, extractI18nKeys(cmd)...)
+		}
+		return keys
+	case *parse.CommandNode:
+		if len(n.Args) >= 2 {
+			if ident, ok := n.Args[0].(*parse.IdentifierNode); ok && ident.Ident == "ctx.locale.Tr" {
+				if str, ok := n.Args[1].(*parse.StringNode); ok {
+					return []string{str.Text}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func searchUntranslatedKeyInTemplateFile(dir, path string, keys []string) ([]string, error) {
+	if filepath.Ext(path) != ".tmpl" {
+		return nil, nil
+	}
+
+	bs, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	// The template parser requires the function map otherwise it will return failure
+	t, err := template.New("test").Funcs(templates.NewFuncMap()).Parse(string(bs))
+	if err != nil {
+		return nil, err
+	}
+
+	untranslatedKeys := []string{}
+	keysFoundInTempl := extractI18nKeys(t.Root)
+	for _, key := range keysFoundInTempl {
+		if !slices.Contains(keys, key) {
+			untranslatedKeys = append(untranslatedKeys, key)
+		}
+	}
+	return untranslatedKeys, nil
+}
+
+func searchUnTranslatedKeyInFile(dir, path string, keys []string) ([]string, error) {
+	untranslatedKeys, err := searchUntranslatedKeyInGoFile(dir, path, keys)
+	if err != nil {
+		return nil, err
+	}
+
+	untranslatedKeysInTmpl, err := searchUntranslatedKeyInTemplateFile(dir, path, keys)
+	if err != nil {
+		return nil, err
+	}
+	return append(untranslatedKeys, untranslatedKeysInTmpl...), nil
+}
+
+func main() {
+	if len(os.Args) != 1 {
+		println("usage: clean-locales")
+		os.Exit(1)
+	}
+
+	iniFile, err := setting.NewConfigProviderForLocale("options/locale/locale_en-US.ini")
+	if err != nil {
+		panic(err)
+	}
+
+	keys := []string{}
+	for _, section := range iniFile.Sections() {
+		for _, key := range section.Keys() {
+			var trKey string
+			if section.Name() == "" || section.Name() == "DEFAULT" {
+				trKey = key.Name()
+			} else {
+				trKey = section.Name() + "." + key.Name()
+			}
+			keys = append(keys, trKey)
+		}
+	}
+
+	results, untranslatedKeys, err := searchTranslationKeyInDirs(keys)
+	if err != nil {
+		panic(err)
+	}
+
+	var found bool
+	for i, result := range results {
+		if !result {
+			if !found {
+				println("unused locale keys found\n---")
+				found = true
+			}
+			println(keys[i])
+		}
+	}
+
+	if len(untranslatedKeys) > 0 {
+		found = true
+		println("\nuntranslated locale keys found\n---")
+	}
+	for _, key := range untranslatedKeys {
+		println(key)
+	}
+	println()
+
+	if found {
+		os.Exit(1) // exit with error if any unused locale key is found
+	}
+}