DOOM BFA is a DOOM 3: BFG Edition source port Based on RBDoom3BFG.

This is the Special Flatpak Edition

It contains all the features of the original with some UX extras for Flatpak

The engine search for the game folder on your system.
If the engine boots with the wrong game files, use the launch argument +set fs_basepath to set right game folder

To install Open platform put the Open Platform .so file on either the game's or the save folder's (~/.var/app/io.github.maddecoder.Classic-RBDOOM-3-BFG/data/.doombfa) base folder.
And the companion .so file on the ~/.var/app/io.github.maddecoder.Classic-RBDOOM-3-BFG/data/.doombfa/base/lib folder along side with any additional file that is required

Known Bugs:

(NOTE: Those bugs only apply to that release)

• Using Open Platform with Steam might result the associated game to be stuck in playing state,
  as a workaround restart the Steam Client
• The engine doesn't boot after installing OpenPlatform with Steam. Try to block access to the wayland socket from the app's flatpak rights
• Loading mods with custom new game entry might not load the custom new game entry. Restart the engine