Namespace packages are a way of splitting a single Python package across multiple directories.
Unlike Regular Packages, where all modules must be located inside the package directory, a namespace package can span multiple directories on disk.
They also do not require an __init__.py file.
I don’t have much experience with namespace packages, so I will not go into more detail here.
The simplest thing I can say is that they shouldn’t be used unless you have a good reason to do so, because they can lead to confusion or problems with importing modules.
If you want to learn more about them, see this stackoverflow answer