Examine source code of Save Browser Sessions

{
  "manifest_version": 2,
  "name": "Save Browser Session",
  "version": "1.0",
  "description": "Save and restore your browsing sessions with ease.",
  "icons": {
    "48": "icons/icon.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_popup": "popup/popup.html",
    "default_title": "Save Browser Session"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e951b7f6-e153-4294-895c-8707ed0f6561}"
    }
  }
}