* \[**Breaking**\] Variant tags are reordered.
 * \[**Breaking**\] Variant names of certain letters are renamed and reorganized, including:
   - `a` and `g`.
   - Upper Gamma (`grek-upper-gamma`).
   - `K`, `k`, Cyrillic Ka (`К` and `к`).
   - Cyrillic Ze (`З` and `з`).
 * Add characters:
   - Cyrillic Iotified E (`U+0464`, `U+0465`).
   - Cyrillic Omega (`U+0460`, `U+0461`), Ot (`U+047E`, `U+047F`), Broad Omega (`U+A64C`, `U+A64D`).
   - Cyrillic Psi (`U+0470`, `U+0471`).
   - Cyrillic Broad On (`U+047A`, `U+047B`).
   - Cyrillic combining Dasia (`U+0485`), Psili (`U+0486`), Pokrytie (`U+0478`).
   - Cyrillic Ornate Omega (`U+047C`, `U+047D`).
   - Cyrillic Koppa (`U+0480`, `U+0481`).
   - Cyrillic Semi-soft Sign (`U+048C`, `U+048D`).
   - Cyrillic Er with Tick (`U+048E`, `U+048F`).
   - Cyrillic tailed Short I (`U+048A`, `U+048B`), tailed El (`U+04C5`, `U+04C6`), railed En (`U+04C9`, `U+04CA`), tailed Em (`U+04CD`, `U+04CE`).
   - Cyrillic Ka with Vertical Stroke (`U+049C`, `U+049D`).
   - Cyrillic Ka with Stroke (`U+049E`, `U+049F`).
   - Cyrillic Pe with Middle Hook (`U+04A6`, `U+04A7`).
   - Cyrillic Abkhasian Ha (`U+04A8`, `U+04A9`).
   - Cyrillic Te-Tse (`U+04B4`, `U+04B5`).
   - Cyrillic Abkhazian Che (`U+04BC` ... `U+04BF`).
   - Cyrillic Ka with Hook (`U+04C3`, `U+04C4`).
   - Cyrillic Ghe with Stroke and Hook (`U+04FA`, `U+04FB`).
   - Cyrillic Ha with Hook (`U+04FC`, `U+04FD`).
   - Cyrillic Ha with Stroke (`U+04FE`, `U+04FF`).
 * Add tailed variants for Cyrillic El, En, Che, Yery and Ya (#972).
 * Add more serifed variants for `K`, `k`, `n`, Cyrillic Ka (`К` and `к`) and Cyrillic Ef (`ф`) to better reproduce PT Mono (#986).
 * Add SS18 to represent Input Mono (#990).