When using a MANIFEST.in with only "include *.txt", on Windows, distutils grabs too many files. I set DISTUTILS_DEBUG=1 and ran ./setup.py sdist on the keyring library and it included this output:

    include *.txt
    include_pattern: applying regex r'^[^/]*\.txt\Z(?ms)'
     adding CHANGES.txt
     adding CONTRIBUTORS.txt
     adding .hg\last-message.txt
     adding keyring.egg-info\dependency_links.txt
     adding keyring.egg-info\requires.txt
     adding keyring.egg-info\SOURCES.txt
     adding keyring.egg-info\top_level.txt

As you can see, this is not a recursive include, but it's matching several files not in the supplied pattern (files in .hg/ and keyring.egg-info/).

It's obvious from the regular expression that the regex doesn't properly account for os.sep.