Examine source code of Cat Companion

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.1",
  "description": "__MSG_extensionDescription__",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icons/cat-icon-16.png",
      "48": "icons/cat-icon-48.png",
      "128": "icons/cat-icon-128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/cat1.png",
    "images/cat2.png",
    "images/cat3.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c33768ea-214e-4bbc-91c5-b232c655c521}"
    }
  }
}