Not tested but looks ok. Could you extend the documentation a bit? Maybe add the expected type of data for the service and an example on how to use it with modify-services? With lirks to relevant sections.

Le 15 mars 2021 14:56:06 GMT-04:00, Leo Famulari <leo@famulari.name> a écrit :
On Fri, Mar 12, 2021 at 05:51:21PM -0500, Leo Famulari wrote:
Does anyone know how we could make it possible for users to change these
new defaults?

With assistance from roptat on #guix, I wrote these patches that work
well and meet all the requirements I had in mind.

Your thoughts? I'd like to push this soon.