How are packages actually found?

[zerothi]

From the doc https://scikit-build-core.readthedocs.io/en/latest/configuration.html#customizing-the-built-wheel it seems to me that <package> and src/<package> are always found.
But it is not fully clear to me what [tool.scikit-build] packages = ["<package>"] does.

What confuses me is its relation to [tool.setuptools.packages.find] where = [ ... ].

I also read your remark here https://github.com/scikit-build/scikit-build-core/issues/269#issuecomment-1505324069 which suggested that [tool.scikit-build] packages only need the top-level package name. Or?

Basically I want to know which of these are needed:

- pack/
  - hello/
  - foo/

and whether I then need to do:

[tool.scikit-build]
packages = ["pack", "pack/hello", "pack/foo"]

or only "pack"?

If the latter then it has no resemblances to setuptools find method.

Also, a comment on namespace packages would be nice. But I'll test and comment here as well. :)