Comment by Arrowmaster

At least the signal one is using the new DEB822 format, but whomever wrote that missed the fact they could have just embedded the key into the sources file and it would be a very simple command.

I'm fairly sure both of those are available from extrepo making them a single short command away. https://manpages.debian.org/trixie/extrepo/extrepo.1p.en.htm...