Snap is interesting in context of Chromium Browser for Kicksecure Discussions (not Whonix) since it provides a source for chromium:
It’s security needs to be researched.
Quote ISV questions about signing a snap - store - snapcraft.io
Snap are signed and snapd checks it before installation.
Does Snap pass the TUF Threat Model, TUF: Attacks and Weaknesses [archive]?