It's not a great idea to make the unstable dev build your primaryshell. If you just want to have it around for testing, you can run it directly out of the build directory when needed. (This is what I do.)
I have the same thing in mind -- I'll run the 'dev' just to see
if I can make myself useful possibly sniffing out a bug, but I
want the stable release to fall back to in case of trouble. I'm
unclear as to the situation with all the rest of whatever files
might be associated with the 'dev' tho. It's easy to just run the
executable, but I'd worry about some other change somewhere else
in the project that might be a dependency -- or is that not going
to be an issue? And then there's, say, Bart's, recent edit to
'zmv' -- will such things be included in a 'git' of the latest?
'make install' does the Linux thing and distributes files here and
there, which is standard, but ... well I dunno, maybe there's
nothing to worry about, but one might suppose that two complete
installations would be required -- one stable and one bleeding
edge. Or not. Maybe just the executable is the only thing that
varies 'dangerously'. None of this is obvious.