@marcan @thephd Yeah, this is actually a nothingburger for everyone. It's not a big deal, and it is basically nothing we didn't already kind of know.
The stupidity around PPDs is the *whole reason* CUPS 3.0 is happening: it rips PPD support out of the whole thing and stuffs it into an external process that talks over IPP (Cf. PAPPL), specifically so that PPD-based printer communication can be locked down even further than it already is.