alt Hacker NewsYou have the wrong measure. Large is number of parts. That is partially source files, partially projects/teams, and partially things that are conceptually not related. Likely other things as well.
It is unlikely GB/TB is ever a measure, though if your repo is that big and some people only need a subset of the repo it would be.
Worked at a place (as a tech writing manager) where the monorepo was several TB and company-issued laptops all had 500 GB hard drives. It was like a rite of passage that new writers or people with new laptops would inevitably not RTFM or learn about sparse checkout and try to clone the entire repo, which was not good.