https://www.kernel.sh/docs/api-reference/browser-pools/create-a-browser-pool#body-chrome-policy

rickrollbrowser.json

{"chrome_policy": {
  "ShowHomeButton": true,
  "HomepageLocation": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
  "HomepageIsNewTabPage": false,
  "RestoreOnStartup": 4,
  "RestoreOnStartupURLs": ["https://www.youtube.com/watch?v=dQw4w9WgXcQ"],
  "NewTabPageLocation": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
  "BookmarkBarEnabled": true,
  "ManagedBookmarks": [
    {"toplevel_name": "Never Gonna Give You Up"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Important Meeting Notes"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Q4 Revenue Report"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Urgent: Action Required"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Password Reset"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Free WiFi Login"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Definitely Not a Rick Roll"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Click Here to Unsubscribe"},
    {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "You Won a Prize!"},
    {"name": "Work Stuff", "children": [
      {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Jira Board"},
      {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Slack"},
      {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "GitHub PRs"},
      {"url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ", "name": "Production Hotfix Guide"}
    ]}
  ],
  "DefaultSearchProviderEnabled": true,
  "DefaultSearchProviderName": "RickSearch",
  "DefaultSearchProviderKeyword": "rickroll",
  "DefaultSearchProviderSearchURL": "https://duckduckgo.com/?q={searchTerms}",
  "DefaultSearchProviderSuggestURL": "https://duckduckgo.com/ac/?q={searchTerms}",
  "DefaultSearchProviderIconURL": "https://img.youtube.com/vi/dQw4w9WgXcQ/default.jpg",
  "DownloadDirectory": "/home/kernel/Downloads/never-gonna-give-you-up",
  "SpellcheckEnabled": true,
  "SpellcheckLanguage": ["Rick Astley"],
  "PopupsAllowedForUrls": ["https://www.youtube.com/watch?v=dQw4w9WgXcQ"],
  "AutofillAddressEnabled": false,
  "AutofillCreditCardEnabled": false,
  "PasswordManagerEnabled": false
}
}