Examine source code of F.C. Twente 65

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Header_FCTwente2.jpg"
    },
    "colors": {
      "frame": "#8c8c8c",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "F.C. Twente 65",
  "manifest_version": 2,
  "description": "The Firefox persona of the football club from Twente, F.C. Twente '65 a.k.a. FC Twente"
}