There is a configuration field for udev rules: https://guix.gnu.org/manual/en/html_node/Base-Services.html udev-service [#:udev eudev #:rules '()]
But there is no configuration option to add a hwdb file. I don't know if that matters but nixos has such option: services.udev.extraHwdb That's the hwdb file I want to add: https://github.com/spiderbit/emacs-ergo-thinkpad-kb-layout/archive/master.zip
