The new feature to use proton with arbitrary executables is a godsend. No more struggling with wine prefixes, we can let Steam handle it.

I intend to use it with ebook DRM crackers, mod managers for Beat Saber and ESO, maybe even non-Steam VR titles, like the Vive store. Maybe some of the crappy desktop clients for enterprise webapps that I need for work too.

please don't, not through steam. i'm sure steam collects some statistics on how people are using proton, and if they start seeing stuff like this show up they might start locking it down again.

you might be able to run proton stand-alone for stuff like this if you really want to. https://github.com/ValveSoftware/Proton