Examine source code of Free Snipping Tool

{
  "manifest_version": 2,
  "name": "Free Snipping Tool",
  "default_locale": "en",
  "description": "__MSG_extDescription__",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "version": "1.0",
  "icons": {
    "128": "images/icon.png"
  },
  "browser_action": {
    "default_icon": "images/icon.png"
  },
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{007346a7-c154-4106-8500-f86c9b6e6475}"
    }
  }
}