Validation issue with undefined LicenseRefs

[armintaenzertng]

In this SPDX document (it is in JSON format, but has .txt extension because of GitHub), the LicenseRef-21495e9 (among others) is used twice in the document, but not defined anywhere.

This issue is not picked up by the java-tools validation.

For reference, the issue came up here.

[armintaenzertng]

Here is the list of all undefined LicenseRefs that the python-tools picked up on:
LicenseRef-21495e9
LicenseRef-1c734cf
LicenseRef-fa9fd02
LicenseRef-4ccf56f
LicenseRef-39c3ee0
LicenseRef-21495e9
LicenseRef-1b79b75
LicenseRef-ca2312b
LicenseRef-45c771b

[armintaenzertng]

Closing due to this comment.