Examine source code of FF13Lightning

{
  "theme": {
    "images": {
      "theme_frame": "HEADER.jpg"
    },
    "colors": {
      "frame": "#610e0e",
      "tab_background_text": "#edb0b0"
    }
  },
  "version": "2.0",
  "name": "FF13Lightning",
  "manifest_version": 2
}