Examine source code of Thief - The Dark Project

{
  "theme": {
    "images": {
      "theme_frame": "Firefox_Theme_The_Dark_Project_Header.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Thief - The Dark Project",
  "manifest_version": 2,
  "description": "Thief - The Dark Project\n\nMy first persona!\n\nIt's about one of my favorite games. Cool Ninja-like stealth feeling! :)\n\nStarring: Garrett, the cool master thief!\n\nThe persona has a width of 3000px, so if you have an adequate resolution you will see Garrett 3 times :) If that ain't cool! :)\n\nNote: I couldn't figure out a good color for \"accent\"... so I hope it works for you!\n\nEnjoy!!!"
}