It's a kernel module. What you do in practice is to have a configuration file somewhere and then have a command line tool (wg(1)) read that file and have the wi

It's a kernel module. What you do in practice is to have a configuration file somewhere and then have a command line tool (wg(1)) read that file and have the wireguard kernel module create a wg0...n network device. The out of kernel alternative is how OpenVPN has always worked, by creating a TUN/TAP device, which basically creates a pipe<->network device bridge, and a user space process reading/writing from that pipe.