I’m using Kopia to back up my local disk.
The repository is created with the “filesystem” provider at an external hard disk.
I’m thinking of the case that my local hard disk breaks completely.
Which Kopia files do I need to backup too, to access the repository (on my external harddisk)?
None really. All what you have to have secured is your repository password.
But it is good idea to try it for example by connecting your external disk to another computer and connecting to the repo. This way when shit hits the fan you will know what to do.