(modify-services %desktop-services (guix-service-type config => (guix-configuration (inherit config) (substitute-urls '("https://bayfront.guixsd.org" %default-susbstitute-urls)) (authorized-keys '((public-key (ecc (curve Ed25519) (q #8D156F295D24B0D9A86FA5741A840FF2D24F60F7B6C4134814AD55625971B394#))))))))