Re: Plugin repository for Ubuntu 19.10
OpenCPN is geared towards using the Ubuntu long term releases, the latest being 18.04 and the next one will be 20.04. There are no repository for the intermediate releases, that I know of.
Having said that I'm running 19.10 myself......
I have not had any problems using the 18.04 - Bionic, repository. So just make sure that you're pointing to the Bionic repository and not to, a non existing, Eoan repository.