Examine source code of Material Design for FF

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Material Design for FF",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(50, 49, 65)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(48, 18, 92)",
      "tab_line": "rgb(253, 88, 19)",
      "popup": "rgb(50, 49, 65)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(146, 35, 249)",
      "button_background_hover": "rgb(253, 88, 19)",
      "frame_inactive": "rgb(248, 31, 131)",
      "icons_attention": "rgb(248, 31, 131)",
      "ntp_background": "rgb(50, 49, 65)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(146, 35, 249)",
      "popup_highlight_text": "rgb(248, 31, 131)",
      "popup_highlight": "rgb(248, 31, 131)",
      "sidebar_border": "rgb(146, 35, 249)",
      "sidebar_highlight": "rgb(253, 88, 19)",
      "tab_loading": "rgb(248, 31, 131)",
      "tab_selected": "rgb(253, 88, 19)",
      "toolbar_field_highlight": "rgb(146, 35, 249)",
      "toolbar_field_text_focus": "rgb(146, 35, 249)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{94333a4c-c5d6-4e1f-b67e-6cc6d444d9ba}"
    }
  }
}