Examine source code of Sessions

{
  "manifest_version": 2,
  "name": "Sessions",
  "version": "1.0",
  "description": "Save tabs and restore them from text file",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "tabs",
    "downloads"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Sessions"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c28f70ff-78cc-4bfb-a4a1-2c7a9082bc98}"
    }
  }
}