This is a development toolkit for phylogenetics. There are many different main packages that are typically in subdirectories. So, for example, the bipartition analyzer is in gophy/bp/ and is called bp.go. To get this code and compile things, just do go get github.com/FePhyFoFum/gophy. Then you can build it with go build github.com/FePhyFoFum/gophy/bp/bp.go. There are other mains in other subdirectories with more to come.
You can find more information here.