Whether to enable an additional systemd service that ensures that the Mullvad VPN daemon will block all traffic early in the boot process, as opposed to blocking traffic after the network has been set up. Enabling this option matches what upstream Mullvad distributes for their supported distros, but is disabled by default in NixOS as it may conflict with non-Mullvad network configurations. If you do not have a custom network configuration, it is recommended to enable this option in order to prevent network leaks during the boot process.
option