Doom 3 BFG Edition features improved graphics, better sound, a checkpoint save system, support for 3D displays, and features various other refinements. Doom 3 BFG is still being powered by id Tech 4 and not the newer id Tech 5 engine as used by the Rage game and the forthcoming Doom 4 title.
id Software hasn't released a native Linux client for Doom 3 BFG Edition even though they did release a native Linux binary for the original Doom 3, which was maintained well during Timothee Bessett's tenure at id Software.
A few months ago id Software said Linux hasn't produced positive results and they are not actively working on any native client ports of id Tech 5 / Rage for Linux, so even though it may not be hard to bring Doom 3 BFG to Linux, I wouldn't be surprised if the company decides to not officially create this port.
While no Linux client for the new BFG release has emerged nor have I heard yet if there are any official plans, they are at least already preparing to release the BFG engine modifications.
John Carmack, the id Software founder, tweeted on Friday: "Got approval for GPL release of Doom 3 BFG code (minus third party bits)! @idBrianHarris has already done most of the work."
It will be just like previous id Tech engine code drops where it comes down to the engine code and not the game art/maps/assets so you still need to buy the media for actually playing the game. This is great to see a very quick turnaround time for getting out the Doom 3 BFG Edition changes.
At least with the code out there, a native Linux version of Doom 3 BFG Edition will hopefully come about -- official or not. It was in November of last year that the original Doom 3 / id Tech 4 code was published although it's not widely used yet amongst open-source projects.