The new awesome HTML API output displays:
uselang ... A list of codes may be fetched from action=query&meta=siteinfo&siprop=languages
The displayed query string is correct -- https://www.mediawiki.org/w/api.php?action=query&meta=siteinfo&siprop=languages would work. But the link in the HTML here is to <a href="/w/api.php?action=help&modules=query%2Bsiteinfo">, which doesn't work, it instead generates help for meta=siteinfo.
Should be an easy fix to includes/api/ApiHelp.php , patch coming...
Version: unspecified
Severity: minor