We want to use only "ks" code for for interface on Kashmiri language. There is a related discussion on the Kashmiri Wikipedia about this task at [[https://ks.wikipedia.org/wiki/%D9%88%D9%90%DA%A9%DB%8C%D9%96%D9%BE%DB%8C%D9%96%DA%88%DB%8C%D8%A7:%D8%A7%D8%A0%D8%B3%D9%8E%D9%85%D8%A8%D9%8E%D9%84%DB%8C_(%D8%AA%D9%8E%DA%A9%D9%86%DB%8C%D9%96%DA%A9%DB%8C) | Technical Village Pump]], where users have supported the request.
[x] Add `ks` to language-data. Redirect `ks-arab` to `ks`. `ks-deva` should remain separate.
[x] Add `ks` to jquery.uls. Redirect `ks-arab` to `ks`. `ks-deva` should remain separate.
[x] Add `ks` to ULS extension. Redirect `ks-arab` to `ks`. `ks-deva` should remain separate.
[] Add `ks` to ULS search index. TODO: Not needed
[x] Add `ks` to Names.php in MediaWiki Core
[x] Redirect `ks-arab` to `ks` in core for backwards compatibility ([[ https://gerrit.wikimedia.org/r/c/mediawiki/core/+/948987 | patch ]])
[x] Redirect `ks-deva` to `ks` in core for backwards compatibility ([[ https://gerrit.wikimedia.org/r/c/mediawiki/core/+/948987 | patch ]])
[x] Declare `ks-arab` as deprecated in core RELEASE_NOTES ([[ https://gerrit.wikimedia.org/r/c/mediawiki/core/+/948987 | patch ]])
[x] Add `ks` to LocalNames in CLDR
[] Deploy core MediaWiki with the new code on translatewiki
[x] Check current translations on translatewiki:
[x] https://translatewiki.net/wiki/Special:LanguageStats?language=ks-arab&suppressempty=1&x=D
[x] https://translatewiki.net/wiki/Special:LanguageStats?language=ks-deva&suppressempty=1&x=D
[x] https://translatewiki.net/wiki/Special:LanguageStats?language=ks&suppressempty=1&x=D
[x] Move all translations in all projects on translatewiki from `ks-arab` to `ks` ( https://translatewiki.net/wiki/Renaming_language_codes)
[x] Verify correct functionality in translatewiki:
[x] Verify all the projects that have `ks-arab` translations: https://translatewiki.net/wiki/Special:LanguageStats?language=ks-arab&suppressempty=1&x=D should be empty after purging
[x] Verify all the projects that have `ks-deva` https://translatewiki.net/wiki/Special:LanguageStats?language=ks-deva&suppressempty=1&x=D should stay as is
[x] Verify all the projects that have ks translations https://translatewiki.net/wiki/Special:LanguageStats?language=ks&suppressempty=1&x=D should have the translations that were previously in `ks-arab`
[x] Export all the projects from translatewiki to Gerrit, etc.
[] Set translatewiki language portal for `ks` to enabled https://translatewiki.net/wiki/Portal:Ks. Redirect Translation tool and Recent Changes from `ks-arab` to `ks`
[] Set translatewiki language category for `ks` to enabled.
[] Prohibit translation into `ks-deva` and `ks-arab` on translatewiki in `mw-config/TranslateSettings.php`
[] Deploy translatewiki configuration with prohibited `ks-arab` and `ks-deva` on translatewiki
[] Test https://translatewiki.net/wiki/Special:ActiveLanguages
[] Test https://translatewiki.net/wiki/Special:ActiveLanguages/ks-arab
[] Test https://translatewiki.net/wiki/Special:ActiveLanguages/ks-deva
[] Test https://translatewiki.net/wiki/Special:ActiveLanguages/ks
[] Deploy updated codes on Wikimedia sites (probably in the train)
[] Remove data tagged as `ks-arab` from Wikidata: delete it or move it to `ks`. Perhaps check with @Iflaq and others if we can proceed with this.
[] Maybe? (Under review!) Remove MessagesKs_arab.php, MessagesKs_deva.php and add `ks-arab` and `ks-deva` to DEPRECATED_LANGUAGE_CODE_MAPPING in core