Change Details

== Pre-deployment checklist [] ensure all subtasks below have passed QA stage (it's ok if QA in production hasn't happened yet) == Acceptance criteria [-] Deploy language button to all logged-in users [x] Decide whether https://gerrit.wikimedia.org/r/c/mediawiki/extensions/UniversalLanguageSelector/+/688994 needs to be backported. It is needed for the A/B test so should be present on the test wikis prior or as part of deployment. (deployed everywhere) [x] Decide if fix for https://phabricator.wikimedia.org/T282540 needs to be backported (available 27th earliest) [] Decide if any patches for https://phabricator.wikimedia.org/T276561 need to be backported (without backport will go out on 10th June) [] Deploy button to test wikis, along with A/B test setup (A/B test will run on users of the test wikis only) - 100% to all anonymous users - A/B test for logged-in users [] Make sure that the language button is not available on wikis where a language button appears next to personal tools (e.g. Wikimedia Commons, Wikidata.org) == List of pilot wikis to exclude from deployment [] trwiki [] fawiki

== Pre-deployment checklist [] ensure all subtasks below have passed QA stage (it's ok if QA in production hasn't happened yet) == Acceptance criteria [-] Deploy language button to all logged-in users [x] Decide whether https://gerrit.wikimedia.org/r/c/mediawiki/extensions/UniversalLanguageSelector/+/688994 needs to be backported. It is needed for the A/B test so should be present on the test wikis prior or as part of deployment. (deployed everywhere) [x] Decide if fix for https://phabricator.wikimedia.org/T282540 needs to be backported (available 27th earliest) [x] Decide if any patches for https://phabricator.wikimedia.org/T276561 need to be backported (without backport will go out on 10th June) [] Deploy button to test wikis, along with A/B test setup (A/B test will run on users of the test wikis only) - 100% to all anonymous users - A/B test for logged-in users [] Make sure that the language button is not available on wikis where a language button appears next to personal tools (e.g. Wikimedia Commons, Wikidata.org) == List of pilot wikis to exclude from deployment [] trwiki [] fawiki

== Pre-deployment checklist [] ensure all subtasks below have passed QA stage (it's ok if QA in production hasn't happened yet) == Acceptance criteria [-] Deploy language button to all logged-in users [x] Decide whether https://gerrit.wikimedia.org/r/c/mediawiki/extensions/UniversalLanguageSelector/+/688994 needs to be backported. It is needed for the A/B test so should be present on the test wikis prior or as part of deployment. (deployed everywhere) [x] Decide if fix for https://phabricator.wikimedia.org/T282540 needs to be backported (available 27th earliest) [x] Decide if any patches for https://phabricator.wikimedia.org/T276561 need to be backported (without backport will go out on 10th June) [] Deploy button to test wikis, along with A/B test setup (A/B test will run on users of the test wikis only) - 100% to all anonymous users - A/B test for logged-in users [] Make sure that the language button is not available on wikis where a language button appears next to personal tools (e.g. Wikimedia Commons, Wikidata.org) == List of pilot wikis to exclude from deployment [] trwiki [] fawiki