I have the same OS and basically the same repo’s on three machines. I had that error (see another post) about update not finding a Signature for a repo.
It took lots of web searching, several posts here, and finally found the repo with the missing key. Got it fixed.
But, I have been looking at all kinds of web search articles and man pages trying to find a way to ‘export’ a PGP Signature key. I thought YaST would have key export, but if it does I can’t figure it out.
Is it possible?
I have not come across a way of exporting keys from the database.
Using Yast Software Repositories, there’s a GPG Keys option which allows adding a key or deleting a key. And you see a list of keys. There is also the “rpmkeys” command for doing similar things.
If I really need a particular key, I would look for the key-identifier with Yast Software Repositories. And then I would use
gpg --recv-key "identifier"
to receive it into my own keyring. From there, I could export it to a file.