It would be fair to mention everywhere the well-known problem with snaps on Ubuntu that dramatically cripples the usability of this otherwise great software. Ubuntu is just the largest Linux distribution by far, and you've lost it...

As I said some years ago, you need an alternative way of communication. Shouldn't be so hard, Mozilla Docs says you can use sockets to communicate with local applications (by Native messaging). It's presumably just plain TCP/IP. Even password managers are mentioned as examples...

Time has come - already in 2021 but I postponed the upgrade so far -, and there is no apt-based version of FireFox as a second choice anymore in Ubuntu, only the Snap Store-based, so we are doomed. I will not go backward installing a browser from a place out of the Ubuntu's own ecosystem. Thank you.

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My response to your response:

Thank you, but an alternative means an alternative. If not the Native Messaging then an encrypted file or similar would have been developed as a way of communication. We talk about years... No way that a FireFox extension can't and couldn't communicate with the outer world.

But as I'm reading here, see the link below that is really easy to find, no doubt, the problem not handling the Native Messaging correctly is in the browsers themselves, and it is already _solved_ after some years in FireFox (in 105..108 betas so far), KeePassXC is working (!) in the tests, I'm about to try it soon. So you are also not informed well enough for some reason...

https://forum.snapcraft.io/t/call-for-testing-native-messaging-support-in-the-firefox-snap/31055/36

It is only in the Beta channel until the next version of FireFox, probably since it is a fresh development from this summer, but it is OK to me because there is a snap of every FireFox beta as well in Ubuntu, and I can install it in parallel to the non-beta version for now if I want.

As I told you, Ubuntu decided sometimes earlier to go with only the snap version of browsers and even if I'm not hundred percent sure it is the best way to go forward, I will not install the less safe and unsupported apt version of browsers again.