Locale with String.indexOf and String.Compare

I reported some bug with the Locale used in String.indexOf and String.Compare.
#69674 , #70353 , #70437
Documentation Locale

I understand the use of a locale to get the DecimalSeparator or the CurrencySymbol or in the date From or ToString, but what would change when use with String.indexOf and String.Compare ?
I made a small exemple “String-Compare-IndexOf-Locale.xojo_binary_project” to download in the feedback #70437 (or download the archive “TextBadEncod-Proj-Text.zip” further down in the same feedback)
I would like to know how I may fill TextArea1 and TextField2 in order to obtain a different result depending of the Locale (except the bug I reported).
You can test Button1=String.Compare and Button2=String.indexOf (Button3=String.indexOf2 does not use TextArea1 and TextField2)

As they intervened on my bug reports, I would like to warn them @robinlauryssen-mitchell and @paullefebvre .
I ask differently my question above: In which way does the locale influence the result of String.indexOf and String.Compare ?

You mean for instance French ?

The LR does not say, but I think this works with Unicode value, which explains why there is also string.indexOfBytes. In that case it should work with all locales.

We spoke, in another topic, about the problem of encoding the accentuated character like é which can be the single character “é” or the two characters “´” and “e”. Maybe the Locale influence this? I know the encoding influence the result.
But no, I don’t mean specially for French instance. I’m curious of having an exemple of which string to compare to which string which give different result depending of locale (same question with indexof, which string to search within which string).

The best way to evidence what is going on with composed versus decomposed characters would be to test.