The source code of the script is located at
maple3142/gitcf, and you can simply copy and paste the script to Workers editor to get your own instance.
Currently, this is running on CloudFlare Workers' Free plan, so don't rely on this instance being available.
Please don't try to use this instance as a GitHub proxying CDN on a website that you expect a high amount of traffic too. Consider deploying this yourself and use that instead.