http://bugs.winehq.org/show_bug.cgi?id=26000
--- Comment #4 from Nikolay Sivov bunglehead@gmail.com 2011-02-06 15:00:20 CST --- I can see one function that should be related to this, see mshtml/npplugin.c:parse_classid. It uses strict string comparing now.
Also this deserves a test to be added to mshtml/tests, it will show do we need 2 cases (upper and lower cased strings) or should we just ignore case.