Currently information about languages is scattered in many places (https://meta.wikimedia.org/wiki/Talk:Abstract_Wikipedia/Representation_of_languages) and CLDR extension only makes it worse (cf T190129: Consolidate language metadata into a 'language-data' library and use in MediaWiki). Also this extension provides no user-facing features by itself. Proposed:
- We create a PHP library directly derived from CLDR data
- Local overrides and names of languages not in CLDR may either moved to MediaWiki core, language-data or the new library created above
If above results in one new library, it is essentially a Librarization of CLDR extension.