Currently it's almost impossible to get a list of urls to wikis that a user (wether or not the current user) has an account on.
site=matrix lists urls but not database codes and lists everything (even (many!) wikis the user doesn't have an account on at all)
meta=globaluserinfo can show only a list of wikis the user has an account on. But doesn't show URLs.
If both of them has atleast something in common I could do it in two requests, but when at it. We may as well add both to both.
Usecase: Do something for all wikis the user is a member on (global Foobar)