Wait, what?
How could someone reconstruct single commits? There was no Git back then! The patch program is quite old (1985), but those patches go back to 1972.
I'd place the explosion around the time of CVS - but that was an explosion of proprietary VCSes. They didn't have to be as good as git, they just had to be better than CVS.
SCCS was contemporary with early unix development, so certainly it's technically possible that there are revision histories going back that far. But I'd have to believe that the early commits in this repo are just release checkpoints. It looks like the most recent stuff (1994) dates from early proto-FreeBSD work.
>Curating and processing available snapshots as well as old and modern configuration management repositories allows the reconstruction of a new synthetic Git repository that combines under a single roof most of the available data