from the OS. Third parties can produce fonts for scripts not officially supported by Apple, and they will work with macOS. On the other hand, this also means that every font for a given script requires its own copy of the script's shaping information in its own "morx" tables.

Other AAT tables (or AAT-specific extensions to standard TrueType tables) allow for context-sensitive kerning, justification, and ligature splitting. AAT also supports variation fonts, in which a font's shape can vary depending on a scaled value supplied by the