deb http://ftp.ru.debian.org/debian bullseye main contrib
deb http://ftp.ru.debian.org/debian bullseye-updates main contrib
deb http://security.debian.org bullseye-security main contrib
deb http://download.proxmox.com/debian/pve bullseye pve-no-subscription
на примере уже скачанного openvpn-repo-pkg-key.pub