A convention I've been following, might as well write it down. When I create a feed, its name is always something.xml, where something is usually rss.#
Sometimes if it's a special version of the feed, the name might indicate that, for example nightlyRss.xml, which says something about the content (one item per day) and the format (RSS, in my case always 2.0).#
And since it's become more common to have a JSON version too, if present its name differs from the XML-based feed only by the suffix. It has the same name except it ends with .json instead of .xml. So the JSON version of the example would be nightlyRss.json.#