* \[**BREAKING**\] Add separate serifed variants for digits `2` through `5`. As a result, current variants are reordered (#1965). Change of variant names:
  - `two`.`straight-neck` → `two`.`straight-neck-serifless`
  - `two`.`curly-neck` → `two`.`curly-neck-serifless`
  - `three`.`flat-top` → `three`.`flat-top-serifless`
  - `four`.`closed` → `four`.`closed-serifless`
  - `four`.`closed-non-crossing` → `four`.`closed-non-crossing-serifless`
  - `four`.`semi-open` → `four`.`semi-open-serifless`
  - `four`.`semi-open-non-crossing` → `four`.`semi-open-non-crossing-serifless`
  - `four`.`open` → `four`.`open-serifless`
  - `four`.`open-non-crossing` → `four`.`open-non-crossing-serifless`
  - `five`.`upright-arched` → `five`.`upright-arched-serifless`
  - `five`.`upright-flat` → `five`.`upright-flat-serifless`
  - `five`.`oblique-arched` → `five`.`oblique-arched-serifless`
  - `five`.`oblique-flat` → `five`.`oblique-flat-serifless`
* Add characters:
  - LOWER HORIZONTAL RULER SEGMENT (U+1CC05)  (Purposed for Unicode 16; L2/21-235).
  - RIGHT VERTICAL RULER SEGMENT (U+1CC06)  (Purposed for Unicode 16; L2/21-235).
  - LOWER RIGHT RULER SEGMENT (U+1CC07)  (Purposed for Unicode 16; L2/21-235).
  - BOX DRAWINGS LIGHT HORIZONTAL AND UPPER RIGHT (U+1CC1B) ... BOX DRAWINGS LIGHT BOTTOM AND LOWER LEFT (U+1CC1E)  (Purposed for Unicode 16; L2/21-235).
  - BLACK NEUTRAL FACE (U+1CC6F)  (Purposed for Unicode 16; L2/21-235).
  - VERTICAL LINE WITH FOUR TICK MARKS (U+1CC90)  (Purposed for Unicode 16; L2/21-235).
  - HORIZONTAL LINE WITH FOUR TICK MARKS (U+1CC91)  (Purposed for Unicode 16; L2/21-235).
  - UPPER LEFT ONE SIXTEENTH BLOCK (U+1CE90) ... LOWER HALF RIGHT ONE QUARTER BLOCK (U+1CEAF)  (Purposed for Unicode 16; L2/21-235).
  - NEGATIVE SQUARED LEFTWARDS ARROW (U+1F8B4) ... NEGATIVE SQUARED DOWNWARDS ARROW (U+1F8B7)  (Purposed for Unicode 16; L2/21-235).
  - LEFT TWO THIRDS BLOCK (U+1FBCE)  (Purposed for Unicode 16; L2/21-235).
  - LEFT ONE THIRD BLOCK (U+1FBCF)  (Purposed for Unicode 16; L2/21-235).
  - UPPER CENTRE ONE QUARTER BLOCK (U+1FBE4) ... MIDDLE RIGHT ONE QUARTER BLOCK (U+1FBE7)  (Purposed for Unicode 16; L2/21-235).
* Fix a disjoint stroke of Outlined Curly `Z` under some weights (#2195).