It's a tiny little utility, but handy for when you're switching between Go projects in your $GOPATH and other projects in ~/workspace, or for when you can't remember who made a Go project or what website they hosted it on. It's mostly written in Go, so is quicker than just a Bash function alone.
Curious how often the speed of Bash has been a problem in this sort of application.
zsh plugin for doing exactly the same, but not bound to GOPATH only: