Examine source code of Open Inbox

{
  "manifest_version": 2,
  "name": "Open Inbox",
  "version": "1.0",
  "author": "Zach Arnett",
  "description": "A simple extension to open your inbox on demand. Customize the URL through the options page.",
  "permissions": [
    "storage",
    "tabs",
    "notifications"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Click to open inbox"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3558242d-b89c-444a-994a-e835e7d214b5}"
    }
  }
}