I've just updated https://www.mediawiki.org/wiki/Mailing_lists and https://meta.wikimedia.org/wiki/Mailing_lists/Overview#Mediawiki_and_technic... . Sorry for the spam, but you really should take a moment to skim and see whether there are lists there you should join. I especially want to single out:
design mediawiki-api-announce mediawiki-i18n -- localisation and internationalisation labs-l -- for when you have a question or request re Wikimedia Labs analytics wikitext-l -- the new Visual Editor & parser
toolserver-l@lists.wikimedia.org