Examine source code of tabkeeper

{
  "manifest_version": 2,
  "name": "tabkeeper",
  "version": "1.1resigned1",
  "description": "saves and restores tabs even when not using a browsing history",
  "icons": {
    "48": "icons/tabkeeper.svg",
    "96": "icons/tabkeeper.svg"
  },
  "permissions": [
    "tabs",
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "tabkeeper.js"
    ]
  },
  "commands": {
    "savequit": {
      "suggested_key": {
        "default": "Ctrl+Shift+S"
      },
      "description": "Saves open tabs"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e86e6b74-e018-4518-9637-7ab560791846}"
    }
  }
}