Applies the kerning to CJK punctuation characters to produce the visually pleasing typography as defined by JLREQ (Requirements for Japanese Text Layout) and CLREQ (Requirements for Chinese Text Layout). Many CJK punctuation characters include glyph-internal spacing. For example, the CJK full stop and the CJK close parenthesis usually have glyph-internal spacings on the right half of their glyph spaces, to give them a constant advance as other ideographic characters. But when they appear in a row, the glyph-internal spacings become excessive. This feature adjusts such excessive spacing. This feature adjusts the glyph-internal spacing for three cases: 1) adjacent characters (pair kerning), 2) at the line start, and 3) at the line end. To avoid the risk of excessive kerning, fonts must have the OpenType `halt` or `chws` feature, or both. If the font doesn’t have either feature, the effect is disabled. This feature implements 4 values: `normal`, `trim-start`, `space-all`, and `space-first`.
Docs: https://docs.google.com/document/d/146Bupkg3nrNALL3bm8UElRd0vsLVH5807xubsnrthDw/edit?usp=sharing
Samples: https://output.jsbin.com/figixaq