My bad - I read that as looking to connect with the T_3.6 secondary USB.
The T_3.6 primary USB to 'PC' works like all the others to support the many interfaces shown on the tools menu through the standard supported 12 MBit/s hardware interface -if not documented on PJRC.com it should be here in the Forum. Please give details of which interface is to be used and what isn't clear.
If the 2nd T_3.6 port is the one at hand - I've only seen host mode interfaces so far.
The USB0 port (the one with the micro-B connector) is only 12 Mbit/sec on Teensy 3.6. Only USB1 can do 480 Mbit/sec. ...
It would help a lot if more people help and contribute. All libs and the core are open source. But only very few people help to extend them or make them better or just fix bugs..
As much I want - at the moment, I have other priorities. In this special case, I'm only interested to use it;-) - for Joysticks, or, someday, usb-memory - I don't want to dig into this USB stuff.Have you used the new HID parser stuff?
What are the best resources to start?