Ok, I dug down on the notes and found Development sprint June 26th, 2017 (I wasn’t part of that sprint though).
It is technically possible to implement, I just think we need to be careful with the user story now that we have adopt-info. As an example, we need to figure out good ways to sync a conflict with an icon changed store side if said icon comes from appstream.
There is also the set-<keyword> work which would affect this. if at anytime in a build someone could say set-description $(cat file-during-build) it would be really hard to sync that in from the store.
Given that we are meeting live in a couple of weeks, I would welcome a discussion there on how to follow up on it.