Python scripts for downloading feeds, including enclosures, and
merging them with an existing feed. This allows me to archive feeds
that have small windows of validity. (e.g., podcasts that only ever
list the most recent item.)

feedarchive.py looks for a feed.ini in the current directory that
tells it what to do:

[feed]
url=http://rss.feed/to/fetch
id=<id of feed to generate>
title=<title of feed to generate>
publish=<URL where the feed will be published>

There are many possible improvements, but this does what I need, for
now.