Without it GZDoom finds not a single WAD, free or not.
Oh. No mystery here if wadsrc_extra/static/iwadinfo.txt does what it looks like (explicitly list all supported WADs and how to identify them). That can't be copyrightable, at least, so that's good news.
Let's see if we can include the list without including any problematic files.
Kind regards, T G-R Sent from a Web browser. Excuse or enjoy my brevity.