Steps to reproduce:
Open a Test Wikidata Item with a mul label (and no other labels) using...

• ...different uselang settings (e.g. John Doe II)
• ...mobile (https://test.m.wikidata.org/) vs desktop (https://test.wikidata.org/).

What happens?

Desktop:

• In English, the heading uses the language name “multiple languages”, but the table (once you show “all entered languages”) uses the language name “mul”.
• In British English, the result is the same.
• In German, the heading uses the language name „Mehrsprachig“, but the table uses the language name “mul”
• In mul, the heading doesn’t show a language name (because it’s not a language fallback in this case), but the table uses the language name “multiple languages”.

Mobile:

• Meanwhile, on mobile, the termbox (mobile termbox, new termbox, termbox v2, etc.) always seems to use “mul” as the language name – except in mul, where you can briefly see the language name “multiple languages” before it gets replaced by JS with just “mul”.

What should have happened instead?

• In all cases the translated full name (e.g. "multiple languages") should be shown in both the heading and in the table (just as in other languages).
• We do not have all the usual translations for the "multiple languages" string yet. So if there is no translation, then our standard language fallback chain applies (e.g. to the English "multiple languages" as a last resort).

Notes:

• Why is the specifically English name “multiple languages” only used when the page is loaded in mul, but not in English itself, nor in any other language?

Acceptance criteria:

• We understand the problem that leads to this issue.
• The problem is solved (or if solving the problem is out of scope then please create a follow-up task so we can discuss it).

Original:
John Doe II is a Test Wikidata item with a mul label (and no other labels).

• In English, the heading uses the language name “multiple languages”, but the table (once you show “all entered languages”) uses the language name “mul”.
• In British English, the result is the same.
• In German, the heading uses the language name „Mehrsprachig“, but the table uses the language name “mul”
• In mul, the heading doesn’t show a language name (because it’s not a language fallback in this case), but the table uses the language name “multiple languages”.

I find this baffling. Why is the specifically English name “multiple languages” only used when the page is loaded in mul, but not in English itself, nor in any other language?

Meanwhile, on mobile, the termbox (mobile termbox, new termbox, termbox v2, etc.) always seems to use “mul” as the language name – except in mul, where you can briefly see the language name “multiple languages” before it gets replaced by JS with just “mul”.