Thread:Talk:Requests for comment/Zero Architecture/Universal Language Selector

"Language dropdown lists vary on X-Subdomain and X-CS" and "Listed high priority languages [, which] are similar to language dropdowns": I don't understand if this is a proposed or existing thing, but it seems to duplicate ULS features in some way; their logic should probably be coordinated, at least when ULS replaces the standard interlanguage wikilinks view (ask Pau)?