Examine source code of MCRACE

{
  "theme": {
    "images": {
      "theme_frame": "firefoxthemetop.jpg"
    },
    "colors": {
      "frame": "#5e8da8",
      "tab_background_text": "#ccd8ff"
    }
  },
  "version": "2.0",
  "name": "MCRACE",
  "manifest_version": 2,
  "description": "Music Persona"
}