As a user, I want a structured language switcher as the default behavior, not just in beta or when I'm fortunate enough to get it as part of a test.
Acceptance criteria
- Add more browser tests
- Structured language switcher is deployed at 100% to mobile web stable channel
- Product owner basic data analysis confirms change is working as expected
- Old language switcher is removed from the codebase
- @dr0ptp4kt to document change on https://www.mediawiki.org/wiki/Reading/Web/Projects/Improve_in-article_language_switching_on_mobile_web with results of tests before sign off
Note this is contingent on T128917: Head-to-head A/B test language switcher alternative.