Comment 11 for bug 1933665

Note that snapd does not require the assertion file to be present, this is a persistent misunderstanding of how ubuntu-image / `snap prepare-image` works.

When you use --snap (or --extra-snaps) with ubuntu-image (and thus `snap prepare-image`), snapd will hash that .snap file and then query the store for a snap-revision assertion matching that hash, and this is how snapd figures out to include the assertions and thus build the image with the snap without the assertion files present. It has never looked at the local assert files, it has always used this hashing method.