go-ethereum/vendor/github.com/karalabe/hid/LICENSE.md

The components of hid are licensed as such:

• hidapi is released under the 3-clause BSD license.
• libusb is released under the GNU LGPL 2.1license.
• go.hid is released under the 2-clause BSD license.
• gowchar is released under the 3-clause BSD license.

Given the above, hid is licensed under GNU LGPL 2.1 or later on Linux and 3-clause BSD on other platforms.