Examine source code of JavaScript Pair Game

{
  "manifest_version": 2,
  "name": "JavaScript Pair Game",
  "version": "1.0",
  "description": "The Concentration or Memory Matching Game is mainly utilized for memory tests & concentration levels of the player. Here, the player needs to find out all the matching pairs of identical cards placed that are face-down on the board & the player can only turn 2 cards at a time",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/pair-logo.png"
    }
  },
  "icons": {
    "128": "images/pair-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{93309ee5-5848-46c8-b4df-913a738ad585}"
    }
  }
}