Some PyPI origins declare `sdist` archives as [[ http://peak.telecommunity.com/DevCenter/PythonEggs | Python eggs ]] files, a legacy format used before [[ https://pythonwheels.com/ | Python wheels ]] became
the standard for distributing Python modules, see [Djangy 0.1](https://pypi.org/project/Djangy/0.1/#files) for instance.
Those files are simple ZIP archives and contain a `PKG-INFO` file located in an `EGG-INFO` folder but currently
they [cannot be processed](https://sentry.softwareheritage.org/organizations/swh/issues/4779/events/?project=9&query=.egg&sort=freq&statsPeriod=14d) by the PyPI loader.
We should add support for loading those type of artifacts into the archive by:
- adding support to uncompress files with `.egg` extension in `swh.core.tarball`
- adapating `swh.loader.package.pypi.loader.extract_intrinsic_metadata` to parse the `EGG-INFO/PKG-INFO` file