Comment 5 for bug 1920266

My repository is still having this issue.

Ethan, you could use `add-apt-repository` to add the PPA on an Ubuntu system (e.g. in a container) and then use `sudo apt-key list` to look at all the installed keys and find the fingerprint of the key for that PPA (matching it using the description and possibly also the filename -- I believe that `add-apt-repository` saves keys to individual files in `/etc/apt/trusted.gpg.d/`).

You can apparently also install `add-apt-repository` on Debian, which would be simpler (it's in the `python-software-properties` package).