Isn't working with "core projects" in the Pharo repository an actual fork of each project?��

One thing is "Kernel" (which is seldom committed outside of the context of the Pharo repo) and another one is Calypso/Iceberg/Zinc, etc.

What's the practical difference (in terms of code) between such a fork and depending on a particular commit/tag of the referenced project?

ps: These are honest, maybe naive, questions, so please answer accordingly.

Esteban A. Maringolo