PsychHID is licensed to you under the MIT license, like
almost all other Psychtoolbox mex files.

PsychHID uses HIDAPI as a backend for low-level USB-HID
device enumeration and HID raw device access.
See http://www.signal11.us/oss/hidapi for website and download
location.

The combined PsychHID binary mex file (the results of merging PsychHID's
MIT licensed code with HIDAPI licensed under the original
HIDAPI license (file LICENSE-orig.txt) is MIT licensed as
already stated.

You could use our included HIDAPI standalone in your own projects
if you wanted -- although it would make more sense for you to get
the most recent source code from HIDAPI's official website. If you choose
to use our version of HIDAPI in your own projects, we give you the
same freedom of license choice we received from HIDAPI's authors,
as follows:

HIDAPI can be used under one of three licenses.

1. The GNU Public License, version 3.0, in LICENSE-gpl3.txt
2. A BSD-Style License, in LICENSE-bsd.txt.
3. The more liberal original HIDAPI license. LICENSE-orig.txt

The license chosen is at the discretion of the user of HIDAPI. For example:
1. An author of GPL software would likely use HIDAPI under the terms of the
GPL.

2. An author of commercial closed-source software would likely use HIDAPI
under the terms of the BSD-style license or the original HIDAPI license.

