For now, Firefox can still be compiled for GTK2. I imagine that as time goes on more and more responsibility of maintaining that port will move to the LTS distr

For now, Firefox can still be compiled for GTK2. I imagine that as time goes on more and more responsibility of maintaining that port will move to the LTS distributions that actually care about that. (This is just what I think is likely to happen, this isn't based on any announcement by Mozilla.)