{
  pkgs,
  config,
  lib,
  ...
}: let
  inherit (pkgs) nur;

  # reference: https://developers.google.com/custom-search/docs/xml_results?hl=zh-tw#advanced-search-query-parameters
  mkLrFlag = languageRestrictions:
    "&lr=" + lib.escapeURL (builtins.concatStringsSep "|" languageRestrictions);

  mkGlFlag = preferredCountry:
    "&gl=" + preferredCountry;

  mkHlFlag = hostLanguage:
    "&hl=" + hostLanguage;
in {
  programs.firefox = {
    enable = true;

    policies = {
      RequestedLocales = ["fr" "en-US" "zh-TW"];

      SearchEngines = {
        Default = "Google Customized";
        Remove = ["Google"];
        Add = [
          (let
            withFlags = x:
              x
              + mkLrFlag ["lang_fr" "lang_en" "lang_zh-TW"]
              + mkGlFlag "fr"
              + mkHlFlag "fr";
          in {
            Name = "Google Customized";
            Alias = "G";
            IconURL = "https://google.com/favicon.ico";
            Description = "Your data yum yum";
            SuggestURLTemplate = withFlags "https://suggestqueries.google.com/complete/search?q={searchTerms}";
            URLTemplate = withFlags "https://google.com/search?q={searchTerms}";
          })
          {
            Name = "Codeberg";
            Alias = "gco";
            IconURL = "https://codeberg.org/favicon.ico";
            Description = "Software development, but free!";
            URLTemplate = "https://codeberg.org/explore/repos?q={searchTerms}";
          }
        ];
      };
    };

    profiles = {
      default = {
        userChrome = ''
          /* Only works in Firefox if layout.css.has-selector.enabled is set to true in about:config . */
          html#main-window body:has(#sidebar-box[sidebarcommand=treestyletab_piro_sakura_ne_jp-sidebar-action][checked=true]:not([hidden=true])) #TabsToolbar {
            visibility: collapse !important;
          }

          /* monofont tweak */
          #statuspanel-label {
            font-family: monospace;
          }
          .urlbar-input-box {
            font-family: monospace;
          }
        '';
        settings = {
          "layout.css.has-selector.enabled" = true;
        };
        extensions.packages = let
          addons = nur.repos.rycee.firefox-addons;
        in [
          addons.sponsorblock
          addons.return-youtube-dislikes

          addons.shinigami-eyes

          addons.consent-o-matic

          addons.tree-style-tab
        ];
      };

      junk = {
        id = 1;
        inherit
          (config.programs.firefox.profiles.default)
          settings
          userChrome
          ;

        extensions.packages = let
          addons = nur.repos.rycee.firefox-addons;
        in [addons.multi-account-containers];

        containers = {
          raisin = {
            color = "purple";
            icon = "fruit";
            id = 1;
          };
          pomme = {
            color = "red";
            icon = "fruit";
            id = 2;
          };
        };
      };

      # Isolate it because it's proprietary
      tampermonkey = {
        id = 2;
        inherit
          (config.programs.firefox.profiles.default)
          settings
          userChrome
          ;

        extensions.packages = let
          addons = nur.repos.rycee.firefox-addons;
        in [addons.tampermonkey];
      };
    };
  };
}