What's the story behind the revision history of Go?

I noticed that the first 4 revisions f6182e5abf5e , b66d0bf8da3e , ac3363d7e788 , 172d32922e72 of the Go source are all from long before Golang was even proposed, the oldest being from 1972. They are also all credited to Brian Kernighan of AWK-ward fame. They seem to be hello, world implementations in C. Is this an easter-egg or is there some practical purpose?