KeePassXC-Browser Firefox extension can not connect to KeePassXC databse on Linux

#!/The Problem

If you are unable to connect the KeePassXC-Browser Firefox extension/add-on to your KeePassXC database, it is likely because you installed Firefox from either the Flatpak repository or the OS built-in Software application. The solution is to install Firefox .deb package via the Mozilla APT repository.

#!/The solution

Try removing the currently installed version of Firefox, and then install .deb package via the Mozilla APT repository.

> Official docs at mozzila.org

sudo install -d -m 0755 /etc/apt/keyrings

wget -q https://packages.mozilla.org/apt/repo-signing-key.gpg -O- | sudo tee /etc/apt/keyrings/packages.mozilla.org.asc > /dev/null

gpg -n -q --import --import-options import-show /etc/apt/keyrings/packages.mozilla.org.asc | awk '/pub/{getline; gsub(/^ +| +$/,""); if($0 == "35BAA0B33E9EB396F59CA838C0BA5CE6DC6315A3") print " The key fingerprint matches ("$0"). "; else print " Verification failed: the fingerprint ("$0") does not match the expected one. "}'

echo "deb [signed-by=/etc/apt/keyrings/packages.mozilla.org.asc] https://packages.mozilla.org/apt mozilla main" | sudo tee -a /etc/apt/sources.list.d/mozilla.list > /dev/null

echo ' Package: * Pin: origin packages.mozilla.org Pin-Priority: 1000 ' | sudo tee /etc/apt/preferences.d/mozilla

sudo apt-get update && sudo apt-get install firefox