There should be an easy way to detect the version of an installed bundle.

For numerous reasons, it would be nice if there was a convenient way to detect the version of an installed bundle on disk, that does not involve launching Tor Browser.

Historically there was a versions file deep within the guts of the bundle that could (and was) abused for this purpose, but with the move to rbm, the file no longer exists.

My initial inclination proposal would be that there will be a file Browser/tbb_verson.json with the relevant metadata.

 {"version":"6.5.2","architecture":"linux64","channel":"release","locale":"en-US"}

The build process can trivially auto-generate something like this, and it can be updated by the standard auto update process.

Inspired by legacy/trac#20792 (closed), legacy/trac#25012 (moved).