firefox removed all my add-ons

[cmm]

Describe the bug
I have a hand-configured Firefox and I like it that way. Today's "home-manager switch" brought in #91724 and now all my add-ons are disabled, I see "Your browser is being managed by your organization" in the preferences, and I cannot reinstall add-ons by hand.

To Reproduce

1. Have an existing Firefox profile with add-ons
2. Do not have any Nix-side Firefox configuration
3. Update to the latest Nixpkgs Firefox version

Expected behavior
Refrain from destroying user's existing Firefox config?

Notify maintainers
@luis-hebendanz @Mic92 @eyJhb

Metadata

• system: "x86_64-linux"
• host os: Linux 5.4.0-56-generic, Ubuntu, 20.04.1 LTS (Focal Fossa)
• multi-user?: no
• sandbox: yes
• version: nix-env (Nix) 2.3.7
• channels(nix): "nixpkgs-20.09pre228453.dcb64ea42e6"
• channels(michaell): "home-manager, nixpkgs-21.03pre256389.555641c5046"
• nixpkgs: /home/michaell/.nix-defexpr/channels/nixpkgs

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute: applications.networking.browsers.firefox

[eyJhb]

I am not a maintainer, but have wanted this in the past.
There is a PR for this here - #105796

EDIT: It also have nothing to do with HM as far as I know

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/reenabling-firefox-plugins-in-nixos-unstable/10348/2

[mtreca]

Possibly unrelated, but I haven't been able to call the home manager wrapper that configures Firefox (see below) since this merge:

  home-manager.users.mtreca.programs.firefox = {
    enable = true;
    package = pkgs.firefox;
    profiles.mtreca = {
      settings = {
        "toolkit.legacyUserProfileCustomizations.stylesheets" = true;
        "browser.urlbar.maxRichResults" = 0;
        "browser.download.folderList" = 2;
        "browser.download.dir" = "/home/mtreca/tmp";
        "browser.urlbar.update1" = false;
      };
      userChrome = builtins.readFile ../../lib/userChrome.css;
      userContent = builtins.readFile ../../lib/userContent.css;
    };
  };

[Mic92]

fixed in #105796