https://bugs.winehq.org/show_bug.cgi?id=55859
--- Comment #11 from Zeb Figura z.figura12@gmail.com --- (In reply to Alex Henrie from comment #9)
difxappa.dll is closed-source and copyright Microsoft. Definitely off limits.
Well, it's off limits if we intend to reimplement it, as I understand. But I don't think reimplementing difxapp is an option. It's shipped by installers, and due to the way MSI works, it's not going to have the same name at runtime.