Package stack provides utilities to capture and pass around stack traces. This is useful for building errors that know where they originated from, to track where a certain log event occured and so on. The package provides stack.Multi which represents a sequence of stack traces. Since in Go we return errors they don't necessarily end up with a single useful stack trace. For example an error may be going thru a channel across goroutines, in which case we may want to capture a stack trace in both (or many) goroutines. stack.Multi in turn is made up of stack.Stack, which is a set of stack.Frames. Each stack.Frame contains the File/Line/Name (function name). All these types implement a pretty human readable String() function. The GOPATH is stripped from the File location. Look at the StripGOPATH function on instructions for how to embed to GOPATH into the binary for when deploying to production and the GOPATH environment variable may not be set. The package name is stripped from the Name of the function since it included in the File location.