This is a notice that the snap ‘make-system-user’ is about to be deprecated. The reasoning for this is that as of snapd version 2.60, system-user assertions can be trivially signed using the snap sign command with the --chain flag, using the same process as model assertions. Please see https://ubuntu.com/core/docs/system-user for instructions.
The snap source code is available here:
https://github.com/canonical/make-system-user
If anyone is interested in taking over maintenance of this snap, please respond to this post and we can discuss a name transfer, otherwise this snap will be unpublished soon.