Description
It says:
Upright Versus Italic
Source Han Mono includes 551 Latin, Greek, and Cyrillic glyphs that were derived from Source Code Pro. The only characters with proportional-width glyphs in Source Han Sans that are not included are for U+FB00, U+FB03, U+FB04, and U+1F16A through U+1F16C.
Also included are 410 italic glyphs that were derived from Source Code Pro. In addition to the lack of italic glyphs for the Greek and Cyrillic scripts, except for U+03C0 π (Greek), the glyphs for the following 26 characters are provided only in upright form for space-efficiency, and because the upright and italic glyphs are identical in Source Code Pro: U+0020 (space), U+002B +, U+003C <, U+003D =, U+003E >, U+007C |, U+007E ~, U+00A6 ¦, U+00AC ¬, U+00B1 ±, U+00D7 ×, U+00F7 ÷, U+2016 ‖, U+212E ℮, U+2190 ←, U+2191 ↑, U+2192 →, U+2193 ↓, U+2194 ↔, U+2195 ↕, U+2196 ↖, U+2197 ↗, U+2198 ↘, U+2199 ↙, U+2212 −, and U+2713 ✓.
The italic glyphs are accessible via two mechanisms:
• By selecting an italic-style font, either by explicitly selecting the font or via an “Italic” style button that is provided by some apps.
• By enabling the 'ital' (Italics) GSUB feature, which is included in the non-italic fonts.