There's this file: https://gerrit.wikimedia.org/r/plugins/gitiles/VisualEditor/VisualEditor/+/refs/heads/master/lib/jquery.uls/src/jquery.uls.data.js
It shows a pretty old version of this data. It is updated almost every week with new languages, as well as fixes in existing languages. This is first done in https://github.com/wikimedia/language-data/ , soon after that in https://github.com/wikimedia/jquery.uls , and soon after that—in the UniversalLanguageSelector MediaWiki extension.
If this VisualEditor repository needs its own copy of jquery.uls, it should regularly update it from upstream at https://github.com/wikimedia/jquery.uls .
If it's not actually necessary, then it should probably be deleted from the VisualEditor repository.