That should somewhat fix it, but now it's already too late on my server, the setting "ssh_user" already contains the public key (and the "public_key" setting still contains a broken/incomplete value) and there's no obvious easy way to guess what was the true value of the "ssh_user" ...
ping @zamentur
c.f. https://github.com/YunoHost-Apps/borgserver_ynh/commit/ebb51846381266f4126ed0c979b9e5b66569050f
That should somewhat fix it, but now it's already too late on my server, the setting "ssh_user" already contains the public key (and the "public_key" setting still contains a broken/incomplete value) and there's no obvious easy way to guess what was the true value of the "ssh_user" ...