Sorry for the late answer.
The macOS Target has been released recently (March 2017) with the release 9.1.4 and this is probably why you are not finding so much information on this new feature.
I can confirm you that the default port for macOS is 8787 instead of 888 and the reason is simple: in Linux and Unix only root can use the ports below 1024.
As you noticed the macOS target is an application and it runs in userspace with the permission of the logged on user or the user which opens the application. This ensure a better security level without limiting the target functionalities. Moreover the macOS target is currently supported in P2P only and not in Managed mode (it can’t be registered to an RC server) .