Thanks for all of this! That is awesome and I am definitely interested in emacs integration ind the inf7 thing. I’ll start with the flatpak just to see it working (EDIT: done, no flames emerging), and then…
build the current development gtk3 version of I7 from source
I’ll need to do this anyway to get the .deb built. One thing that jumps out is that libgtksourceview-2.0 is required to compile and has been obsoleted out by Debian in the meantime. Reading the other thread it seems like some effort is going on to get non-obsolete dependencies compiling (eventually?); I’m probably not up for duplicating that effort so I might try @interactivefiction’s approach of importing gtksourceview-2.0 into the source tree and building it locally.
That said: as the compilation accumulates more and more obsolete libraries into its build, it kinda converges with the flatpak I guess. This is probably a method with a limited lifespan.