Exaggerative title aside, it's really cool to learn about how fsspec lets you essentially make a custom filesystem in a few lines of code, as well as the (important) notion that the very existence of a Python package can cause a plugin to be installed at a deep level, to be used automatically by other packages.

https://filesystem-spec.readthedocs.io/en/latest/developer.h...

https://setuptools.pypa.io/en/latest/userguide/entry_point.h...

(As a side note here, you might think that "pip install" can only add functionality, and that you can add extra packages locally for your convenience, or keep them around when you switch branches, without having your dev environment diverge from production behavior. But if they register plugins with other packages via the entry point functionality, you might end up coding things that depend on behavior that's not present in other environments! This is especially common in the pytest ecosystem. CI is vital here!)