I'm curious as to the reason why custom exceptions are not allowed (see https://reuse.software/faq/#custom-exception).

For example, I'd like to add a custom exception for https://www.kicad.org/libraries/license/ which is an exception to the Creative Commons CC-BY-SA 4.0 License, but is not registered in https://spdx.org/licenses/exceptions-index.html

For example, I'd like to be able to specify something like this:

SPDX-License-Identifier: CC-BY-SA-4.0 WITH LicenseRef-KiCad-Libraries-Exception

Thanks,

Chris