Meiyo Peng <meiyo@riseup.net> writes:

> * gnu/packages/notification.scm: New file.
> * gnu/local.mk (GNU_SYSTEM_MODULES): Add it.

Looks like Gábor committed a version of this in
46dc940c9af3d8b48966d16e52273ba88e92f946.

Sorry for the duplicate work!