That what I used git submodules for. I had a /lib folder in my project where the dependencies were pulled/checked out from. This was before I was doing CI/CD and before folks said git submodules were bad.

Personally, I loved it. I only looked and updating them when I was going to release a new version of my program. I could easily do a diff to see what changed. I might not have understood everything, but it wasn't too difficult to see 10-100 line code changes to get a general idea.

I thought it was better than the big black box we currently deal with. Oh, this package uses this package, and this package... what's different? No idea now, really.