http://bugs.winehq.org/show_bug.cgi?id=11847
--- Comment #6 from foobard jens@porup.com 2008-03-08 11:13:05 --- in addition to the .idx and .pdx files in the help directory, the Howto/ENU directory includes 40 or so html files, which appear to include the content that should appear in the Help screen.
As an entirely uneducated guess, perhaps Adobe is using some sort of proprietary web browser inside of Acrobat Pro (and perhaps other products too)?