Looks very similar to what Upspin ( Go ) errors look like:

https://github.com/upspin/upspin/blob/master/errors/errors.g...

    type Error struct {
        // Path is the Upspin path name of the item being accessed.
        Path upspin.PathName
        // User is the Upspin name of the user attempting the operation.
        User upspin.UserName
        // Op is the operation being performed, usually the name of the method
        // being invoked (Get, Put, etc.). It should not contain an at sign @.
        Op Op
        // Kind is the class of error, such as permission failure,
        // or "Other" if its class is unknown or irrelevant.
        Kind Kind
        // The underlying error that triggered this one, if any.
        Err error

        // Stack information; used only when the 'debug' build tag is set.
        stack
    }