We should replace this module with Codex markup / library
https://codesearch.wmcloud.org/deployed/?q=mediawiki.ui.button&files=&excludeFiles=&repos=
Checklist
priority 1
- Fix login page https://gerrit.wikimedia.org/r/c/mediawiki/core/+/919361/
- Fix MobileFrontend and Minerva (T340262)
- Fix MultimediaViewer on page load T340258
- Fix Popups T340256
- Fix UniversalLanguageSelector on page load T340255
- Deprecate the module
- communicate changes per https://www.mediawiki.org/wiki/Stable_interface_policy/frontend > T346468
priority 2
- Fix MultimediaViewer (remaining usages) T340258
- Fix NearbyPages
- Fix WikiLove https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikiLove/+/932477
- Fix UniversalLanguageSelector (remaining usages) T T340255
- Fix ContentTranslation
- Fix GuidedTour
- Fix Translate extension T343454
- Fix Oauth extension
- Remove code after 1-2 releases.