Examine source code of FF Nightly Darker

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "FF Nightly Darker",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(82, 82, 94)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(34, 34, 34)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(255, 255, 255, 0)",
      "popup": "rgb(27, 27, 29)",
      "popup_text": "rgb(255, 255, 255)",
      "ntp_background": "rgb(10, 10, 11)",
      "popup_border": "rgba(11, 18, 25, 0)",
      "popup_highlight": "rgb(71, 71, 71)",
      "tab_loading": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7db87428-dc5c-4a20-a956-83a9b7efad31}"
    }
  }
}