[rvz]

...A test suite, And security audits, And most importantly benchmarks.

What it does have is a license which it is GPLv3. So if anyone adds all those changes, they have to make the source code available with the same software license.

[pixel_popping]

In this era tho, licenses (I don't agree with this, but this is what it is) are a matter of "tokens", I speak for a fact knowing multiple relatively-big companies just gobbling GPLv3 projects and rewriting them entirely, some do publish them as well.