Examine source code of CarbonFox2

{
  "theme": {
    "images": {
      "theme_frame": "carbonfox2_head_final2.jpg"
    },
    "colors": {
      "frame": "#52bdde",
      "tab_background_text": "#52bdde"
    }
  },
  "version": "2.0",
  "name": "CarbonFox2",
  "manifest_version": 2,
  "description": "Smooth, sleek carbon-look FireFox themed Persona."
}