Looks like it's the following entry in UnicodeData.txt (which we will hopefully use as a source for our utf-8 ctype maps soon):So, what's going to happen with ß when used through that API?
We have the same problem in Eastern Armenian: և becomes ԵՎ when upper-cased.
0587;ARMENIAN SMALL LIGATURE ECH YIWN;Ll;0;L;<compat> 0565 0582;;;;N;;;;;
Same for ß:
00DF;LATIN SMALL LETTER SHARP S;Ll;0;L;;;;;N;;;;;