anbox: snap is unusable due to missing files
Solution 1:
You answer resides in this thread that I've just found out about:
https://forum.snapcraft.io/t/cannot-install-snap-file-snap-is-unusable-due-to-missing-files/25719
The new unsquashfs update that you've probably installed 2 days ago gives a bug into the new snap package. We need an update as notified in the thread of snapd