https://github.com/jonwwilkes/purr-data is out of sync
Jonathan, you forked https://github.com/jonwwilkes/purr-data from my GH mirror at https://github.com/agraef/purr-data in order to upload your releases. Which is all good and fine, but you never sync that repo with upstream, and so your release tags at https://github.com/jonwwilkes/purr-data/releases all point to the same long out-of-date revision 1f41004d. (In case you're wondering, that's also why it says on the overview page that "This branch is 366 commits behind agraef:master.")
I wouldn't be worried about this, but I see that your repo there has been forked at least two times already, so at least some people seem to think that it is the real thing, when it's just an out-of-date clone being used as a download area.
Fixing this is simple. In your local working copy of firstname.lastname@example.org:jwilkes/purr-data.git, just add email@example.com:jonwwilkes/purr-data.git as a remote named, say,
github. Then, whenever you're about to upload a release, just run
git push github. Your fork there will be up-to-date and you can then create the release tag and upload your release on GH to the proper revision.