Are you sure? Because that's a waste of resources. I'd imagine they would cache the results, which would make the GP's concerns about speed valid.

Edit: Found the github repo - https://github.com/tomocchino/isfiberreadyyet

Looks like it fetches from the umbrella issue[1]

https://github.com/facebook/react/issues/7925

It fetches from GitHub. The website was built in a weekend by our manager to make the task of a complete rewrite a little more fun for the team. Sorry it’s not perfect! ;-)