git being a version control system, all versions and revisions are available through the history.
I didn't check but there certainly are branches for main versions, look there first.
If not, you'll have to browse the commits and locate the revision when main files went to version 2.0.
Yes there is a 1.1 branch but the skp there is from de 2.5 version
and navigating into the history is very odd to me because you can only view historic from a file note the master...
But I'll search more I guess