In my case, KeePass and ExpressVPN could not function. For KeepassXC, this was the reason:
It is impossible to support native messaging when a browser is running as a sandboxed snap. This is a limitation in snapd not keepassxc.
It appears they found some work-around with an extra script after installation as of 2 years ago. Basically, snaps are sandboxed, which is a feature. That wreaks havoc with certain tools, though. ExpressVPN’s browser plugin was having similar problems, and on Linux, that’s you’re only GUI interface for ExpressVPN.
I just checked, and I was updated to the Snap version, and I had no problems with either extension, so they did solve the problems. Therefore, I’m not outraged. Ubuntu has the right to standardize their deployments on a system that makes their work easier or less chaotic - as long as it does not screw over their customers.
Edit: i was mistaken. I still use the Mozilla PPA, so the problems migjt remain.