Examine source code of Open Public Profile

{
  "manifest_version": 2,
  "name": "Open Public Profile",
  "version": "1.0",
  "description": "Quickly open public profiles on Facebook, LinkedIn, and Twitter.",
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icons/icon-48.png",
    "default_title": "Open Public Profile"
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4f6e3623-ac77-4b66-ac22-16cad15ba5ba}"
    }
  }
}