Examine source code of Tag People

{
  "manifest_version": 2,
  "name": "Tag People",
  "version": "0.0.4resigned1",
  "browser_action": {
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.facebook.com/*",
        "http://www.facebook.com/*",
        "*://*.facebook.com/*",
        "*://facebook.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6c91b130-1126-4b18-b575-76da3a0a5727}"
    }
  }
}