I think you read that backwards. In skydhash's test, Codeberg's data was 72% cached, and GitHub's data was 28% cached. Maybe you meant that GitHub's cached 4.28MB was, in absolute terms, more than Codeberg's cached 1.41MB?
The transferred part is for the gzipped transfer. That makes sense if the bulk of the data is HTML (I have not checked).
I’ve disabled the cache for the network requests.