lxd-imagebuilder fits within the supported category of compilers - however, given the original list of requirements for distrobuilder in Request for classic confinement: distrobuilder I wonder if it might be possible to try and strictly confine lxd-imagebuilder in the future? @tomp could you please try and look into this in the future?
For now, the requirements for classic confinement are understood and I have vetted the publisher. This is now live.
As a general rule, snaps owned by the Canonical publisher account should have revisions in stable and have proper maintenance.
Looks like the lxd-imagebuilder snap currently does not have any stable releases. Let me know once there are releses on stable and I will happily complete the transfer.