This has been a problem for a while now. That green dot and popup notification persisted on my Mullvad browser makes me feel like using a bloatware than a FOSS.
The right way to do this is either follow their upstream Tor browser update model—just force updating seamlessly without any user interaction. Or, like LibreWolf, manual update with the system package manager.
This situation might be because of I’m using the portable version of Mullvad browser. If that’s the case, I shouldn’t blame it.
But for anyone on the same boat, who probably uses Mullvad (or any other Firefox based) browser by extracting the package file mullvad-browser-linux-x86_64-*.tar.xz, there is a easy fix with Firefox policy.
On Linux, most Firefox forks reads the system-wide policy file from /etc/firefox/policies/policies.json, but this is not for Mullvad.
The path has to be its working directory ./mullvad-browser/Browser/distribution/policies.json
By creating that file with following content:
{
"policies":
{
"ManualAppUpdateOnly": true
}
}
The annoyances are permanently gone.
What I don’t recommend is to add "DisableAppUpdate": true, which prevents updater process from running at the background and also disables the manual/check update button (hamburger button - help - about - update to).
Keep browsers updated is very important for modern online surfing (sound like a boomer xD). So, make sure you are able to manual update them proactively. The whole purpose of disabling the autoupdate notification is for a peaceful and under-control user experience only.
This method should work across platforms, happy hacking!