I've now cleaned up the Neon repositories published at packaging.neon.kde.org.

For the record, this is cleaned up by first logging in to root@code.kde.org, and running the following command to send a list of the current repositories over to the server that hosts packaging.neon.kde.org:

scp ~neon/projects.list root@elder.kde.org:~neon/master-repos.list

Once this is done, you logout of code.kde.org, and login to root@elder.kde.org, then switch to the neon user.

Once running as neon@elder, you run the following commands to determine which repositories to remove:

cat master-repos.list | sort -n > ~/remote-repos
python3 ~/list-debian-repositories.py | sort -n > ~/local-repos
diff -u ~/local-repos ~/remote-repos

Any line marked with a - should be physically removed, by changing to /media/neon/repos/ and running rm -rf on the path where the repository is located.

In this instance I did:

neon@elder:/media/neon/repos$ rm -rf neon-packaging/rkward.git/
neon@elder:/media/neon/repos$ rm -rf forks/rsibreak.git/
neon@elder:/media/neon/repos$ rm -rf backports-xenial/pyqt5.git/
neon@elder:/media/neon/repos$ rm -rf backports-bionic/appstream.git/