Examine source code of Copy Me That

{
  "name": "Copy Me That",
  "version": "1.4.0",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "incognito": "spanning",
  "permissions": [
    "activeTab",
    "https://*.copymethat.com/*",
    "contextMenus",
    "cookies"
  ],
  "browser_action": {
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "run_at": "document_idle",
      "matches": [
        "https://*.copymethat.com/*"
      ],
      "js": [
        "set_existence.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "exists.gif",
    "spinner_25.gif"
  ],
  "icons": {
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{864ff066-4e8a-451b-b27b-b63f2bf8760a}"
    }
  }
}