[DE] MacOS (Big Sur or M1) uses multi character German umlaute

[Gummibeer]

What is this feature about (expected vs actual behaviour)?

MacOS filesystem replaces German (single character) umlaute with a two characters since Big Sur or only on M1 machines.
These are replaced with a simple a instead of ae. Expected behavior would be to replace these combined characters the same way as the single character umlaute are treated.

How can I reproduce it?

• create a new file or folder with ä, ö or ü - persist the filename (ENTER)
• open the filename change dialog and copy the shown ä/ö/ü character
• run it through the ASCII class

The real-world scenario would be to sanitize an uploaded filename.

Does it take minutes, hours or days to fix?

The local fix took minutes (added a str_replace() before running the ASCII conversion) but no idea how much it will take to properly add it to the package.

Any additional information?

In hope that GitHub doesn't replace the characters - here it is ä - the codepoints are U+61 U+308.
https://www.fileformat.info/info/unicode/char/61/index.htm
https://www.fileformat.info/info/unicode/char/308/index.htm

I'm not sure if this would be the expected behavior of the package or I want it to do something that's not in the scope of that package. We have a working solution right now - so it's in no way urgent.