Examine source code of Facebook Enhancer

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0.0",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "activeTab",
    "webRequest",
    "webRequestBlocking",
    "https://*.facebook.com/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "css": [
        "content.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ac80d902-ad5e-4e0e-85dc-f681a5f145df}"
    }
  }
}