Adopted new calico cat question about fur pattern naming

I've been researching calico cats as I'm going to collect one tomorrow that we are adopting and after stumbling across this video https://www.instagram.com/thecatdaddy/reel/C72ZTVFynCQ/ I notice he mentions they are part of the "GG"?! fur pattern which encompasses calico and tortoise cats. I've googled heaps and can't seem to find anything about the GG fur pattern. Just reaching out to see if anyone else knows. Maybe I'm spelling it wrong 🤔