[gog]

There is a "Star this repo" option for just this case.

But forking has its benefits if you want to make sure that the original repository does not disappear.

[fapjacks]

I'm not sure if this is what you're talking about, but unfortunately, I've had a few repos disappear because the original was served with a DMCA. Github is fast when presented with a DMCA (but also equally fast when presented with a counter-DMCA notice, thankfully). You'll need to clone it off of Github if you really want to ensure its survivability.