The files are here: https://phabricator.wikimedia.org/diffusion/ECLD/browse/master/LocalNames/
Currently we have to modify the repository manually, like T162406: Add Scots names for languages
The files are here: https://phabricator.wikimedia.org/diffusion/ECLD/browse/master/LocalNames/
Currently we have to modify the repository manually, like T162406: Add Scots names for languages
See also T89947: Move special page alias translations to JSON for a similar effort elsewhere that recently gained traction (wikitech-l announcement).