Examine source code of Writing Prompt Tab

{
  "manifest_version": 2,
  "name": "Writing Prompt Tab",
  "version": "1.0",
  "description": "Show a daily writing prompt every time a new tab is opened.",
  "permissions": [
    "storage"
  ],
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7b2bbd18-ea46-4538-b2ec-e4224cb00b64}"
    }
  }
}