Examine source code of Web Essentials

{
  "manifest_version": 2,
  "name": "Web Essentials",
  "description": "Interacts with Visual Studio extensions supporting Browser Link",
  "author": "Mads Kristensen",
  "version": "1.3resigned1",
  "icons": {
    "16": "img/icon16.png",
    "48": "img/icon48.png",
    "128": "img/icon128.png"
  },
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "page_action": {
    "default_icon": {
      "16": "img/vs16.png",
      "20": "img/vs24.png",
      "24": "img/vs24.png",
      "32": "img/vs32.png"
    },
    "default_title": "Web Essentials",
    "default_popup": "popup.htm"
  },
  "web_accessible_resources": [
    "page.js"
  ],
  "offline_enabled": true,
  "permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a52d7243-576e-4e45-a679-4bd6fa76dfcc}"
    }
  }
}