(Please keep commons-l cc-ed, not everyone is subscribed to mediawiki-i18n. :)

Could the extension can, or be tweaked to, help with our other multilingual content?
LS is already deprecated and should be killed at least for templates (multichill told me very few if any still use it, right?);
Well, it has more than 3.7 millions transclusions… See also <https://commons.wikimedia.org/wiki/Category:Internationalization_templates_using_LangSwitch>

Just asking: would it play nicely with our AnonymousI18N script?
If it's what I remember, that would be superseded.

AFAIK, AnonymousI18N handles the following :

* Language selection
 → Handled − that is kind of the purpose of the Universal Language *Selector* right ? ;-)

* Language suggestion, based on « data from cookie, referal url & browser settings »
"referal" means that AnonymousI18N can detect that your  are coming from it.wikipedia.org, your interface should be in Italian
→ What about ULS ?

* Language “uselang” persistency, regardless of the previous
Meaning, if landing on Commons from a URL with ?uselang=fr (obviously from templates on projects, but also from links everywhere [people like me who always tweet/write links with a uselang ;-)]), the ?uselang=fr is set for all outbound links, meaning language persistency.

→ ULS does not appear to do that from my test on TranslateWiki.
(Arriving from <https://translatewiki.net/?uselang=it>, interface in Italian ; clicking a link, interface in French)