Many wikis do not have interwiki language links setup.
This includes 3rd parties, wikitech and mediawiki.org
Thus the new language switcher should be feature flagged, disabled by default and configured on.
This wasn't a problem with the old language switcher as if no languages were available it would be hidden, but with the new language switcher it is always shown.
You can demonstrate this by visiting any page in the mobile beta. Every page shows a disabled language switcher button.
Acceptance Criteria
- Ensure this does not interfere with EventLogging logic for Main Page (T131093)
- The feature flag and its default value are documented on-wiki