Examine source code of Tab Save & Restore

{
  "manifest_version": 2,
  "name": "Tab Save/Restore",
  "description": "Save and restore your windows and tabs",
  "version": "3.0",
  "applications": {
    "gecko": {
      "strict_min_version": "57.0",
      "id": "avbhatt@umich.edu"
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": "icons/tabs-32.png",
    "default_title": "Save/Restore",
    "default_popup": "popup/save_restore.html"
  }
}