If you are a SteamVR Tracking licensee with Valve Software Corporation then the rest of the schematics will be part of your Steam directory on your PC. Valve created the SteamVR Tracking HDK and it is Valve's property. The HDK is free to license and royalty free but you must first go through a click-through-licensing process on their website to access the full schematics.
Information about obtaining a free SteamVR Tracking License from Valve Corporation is available here: https://partner.steamgames.com/vrtracking/
Triad provides a one page schematic of the Shoto HDK to show where original HDK has been modified for the smaller Shoto form factor.