There's still a Preferences option to opt out of "Play DRM-controlled content", even though I'm sure <5% of people opt out of that. Some options stick around for the sake of principle.
It's disabled by default. Enabling DRM installs a non-free binary from Google, and the user is prompted to install it when a website attempts to play DRM media: https://support.mozilla.org/en-US/kb/enable-drm
I wondered why they set it up like this. TIL
That might be just the motivation needed to create a fork.