Agree, and not just that, it allows to escape the hijack of your right click (something google does not tolerate), but they also degraded a lot the experience the last year or two. Number of modal dialog boxes every time it updates (and of course repeat for how many machines you use), also every time there is a pending update, the performance seems to degrade until you close and update, and those updates are very frequent. I don't know if it is my machine but it seems to be struggling when there is more than 2 or 3 video streams on different tabs (increasingly common now that every news websites seems compelled to live stream video on their front page whether you want it or not).

You may restrict updates in policies.json[1][2]:

  {
    "policies": {
      "AppUpdateURL": "http://127.0.0.1/",
      "DisableAppUpdate": true,
      "DisableFirefoxStudies": true,
      "DisableSystemAddonUpdate": true,
      "DontCheckDefaultBrowser": true,
      "ExtensionUpdate": false,
    }
  }

File should be located in $FIREFOX_DISTRIBUTION_DIR/distribution/

$FIREFOX_DISTRIBUTION_DIR is the installation directory for firefox, which (for default setup) probably will be printed by this:

  sed -nE 's/^\s*exec (.*\/)firefox .*/\1/p' $(which firefox) # and it's probably /usr/lib/firefox

[1] https://firefox-admin-docs.mozilla.org/guides/policies-confi...

[2] https://firefox-admin-docs.mozilla.org/reference/policies/

I got very annoyed by the pending update pop-ups and the "Restart to keep using Firefox" messages when I opened new tabs, so I switched over to Librewolf and now I get no distracting modals at all and can update it precisely when I feel like it.