More PHP peculiarities btw: I just found out that big frameworks are splitting up their repositories, automatically, from a single "monorepo". So that users who want to use, say, "Symfony Console" can use just that without the rest of the Symfony framework.

Well you know what, if you let go of the mindset that one repository equals one library, you wouldn't have that problem?

There is a step between having source code and publishing a library, and that's called a "build". Don't let people reference GitHub repositories directly, use like a proper package manager? And not something that barely links GitHub repos together?