At the root of Open Source is you, the user, have the right to the
source code.
In the early days, that's as far as it went but especially after the
Morris Worm, security became very important, Open Source afforded
users the ability to inspect the code for vulnerabilities in ways that
you could not if all you had was the binaries.
But open source should have fixed versions, if possible.
Look at C compilers. I need a K&R C compiler for say 8088 build.
I might not want the latest C standard.
What version has the fewest bugs.