firefox: correct capitalization in extension check error

        throw "Nix addons are only supported with signature enforcement disabled and addon sideloading enabled (eg. LibreWolf)"

      else builtins.map (a:

        if ! (builtins.hasAttr "extid" a) then

        throw "nixExtensions has an invalid entry. Missing extid attribute. Please use fetchfirefoxaddon"

        throw "nixExtensions has an invalid entry. Missing extid attribute. Please use fetchFirefoxAddon"

        else

        a

      ) (lib.optionals usesNixExtensions nixExtensions);