In feeds that do not have a url tag in entries, but an enclosure tag …

In feeds that do not have a url tag in entries, but an enclosure tag with an url attribute instead (e.g. itunes podcasts), use the enclosure URL as the entry URL.

Before this, the URL in these cases defaulted to the guid for each entry, which wasn't necessarily an URL (and even if it was it could be different from the enclosure-url). The enclosure-url was being ignored.