Oh hai!
You can add a "release: 2" line to the article markdown in case you fudged up a release and would like to increment the GUID in the feed after a fix
You can add a "published: false" line to the article markdown to NOT have it show up anywhere.
Feed with all items:
/podcast_feed/all/m4a/rss.xml
Examples for the category feed generation:
/podcast_feed/spezial/mp3/rss.xml
/podcast_feed/talk/opus/rss.xml
iTunes feed that uses m4a with a fallback to mp3 if there is no m4a for that episode
/podcast_feed/talk/itunes/rss.xml
Note: You can also add a feed_size parameter and a page parameter to the URL ("?feed_size=4&page=3")