This language selector has replaced the languages I selected for displaying Wikidata labels and descriptions -- and those were the languages I used -- with "English", "British English". "French" and "Latina". Why? English, French and Latin are fine for me, but British English is useless, a total waste of space. There is no British English wiki. Why did someone decide I must have those four? I want to get "German" and "Portuguese" alongside "English" and "Latin" and "French". Why can't I do that? Why didn't this system take note of the choices I had already made or of the way I really work?
On the project page I see the words "you can also do a more detailed work for a single country, see for instance: bug T64346, bug T141650, bug T142070". Maybe I need to do that, but how? Following those links explains nothing.
I also see the words "ULS queries a service that determines your originating country based on your IP address". That doesn't seem to help me: I live in France. No sensible machine would imagine that two forms of English are among the three most important languages in France.
I also see the words "A small popup (technically called "undo popover" or "tipsy") will also appear when ULS changes the language compared to your previous setting". That would be nice, but it seems to be fantasy.