Data in this summary is limited to the 100 most recent episodes in the feed.
At least that was the case until November 2016, when Marco pointed out to me that there was, indeed, a better place for me to scrape episode data.
In the meantime, I had taken John's advice and started downloading every ATP episode ever as mp3 to manually mediainfo the duration out of them in a script, only to realize that the first few episodes didn't have title information in them. This left only the option of crawling the ATP website for full episode metadata (which is annoying because of non-trivial URL parameters for pagination), which I was very much about to do… until I got Marco's reply.
So… thanks Marco for saving me from the horrible fate that would have been a while loop in R.