Issues with en-us, en-gb, fr

I am looking at the translations of en-us, en-gb and fr.

I think the language used in MuseScore is US English, right?

In the source words like "color" and "measure" appear, which are translated to "colour" and "bar" for British English (however, not all occurrences of "measure" are translated to "bar"). The en-gb translation is pretty complete (at time of writing, only 27 strings not translated).

The en-us translation is rather incomplete, there are 2092 untranslated strings and 20 suggestions, many of them empty. If you look at the "translations" (there are about 270), they mostly change the case of the strings or append colons (:), and then there is this beauty: "Auto" in en-us is "s" (translated by Thomas).

So my questions:
What is the en-us translation used for? Is it used? Is it used to fix capitalisation and spelling mistakes? - like "digonal" becomes "Diagonal". Or perhaps "digonal" was indeed intentional, the word exists and is translated to "digonal (rotiert)" in German (rotiert meaning rotated). BTW, I coudn'f find "digonal" in the source.

Does it make sense to store translations for British English if the translation and the source are identical? Wouldn't it make more sense to flag a translation as identical (without storing it), so it doesn't show up as untranslated.

Looking at French: There are zero untranslated strings, yet 86 suggestions. Should those be reviewed or deleted?