The documentation says that guess_type() takes a URL, but:

>>> mimetypes.guess_type("http://example.com")
('application/x-msdownload', None)

I suspect the MS download is a reference to *.com files (like DOS's command.com). My current workaround is to strip out the host name from the URL, since I cannot imagine it would be useful for determining the content type. I am also stripping the fragment part. An argument could probably be made for stripping the “;parameters” and “?query” parts as well.

>>> # Workaround for mimetypes.guess_type("//example.com")
... # interpreting host name as file name
... url = urlparse("http://example.com")
>>> url = net.url_replace(url, netloc="", fragment="")
>>> url
'http://'
>>> mimetypes.guess_type(url, strict=False)
(None, None)