Why is there inconsistent license terms in the source?

[ajCameron]

E.g. requirements is CC and most of the rest of the source is BSD-2.

[ajCameron]

Also - should actually sort the license - need to specify the year and owner

[javajawa]

Files without novel content are considered not copyrightable. This is a bit of an edge case when it comes to the SPDX/Reuse specification, but CC0-1.0 is recommended https://reuse.software/faq/#uncopyrightable.
There's various discussions about who the owner should be marked as in that case.

I believe that the design docs also have a CC4 license on them, as they don't contain code and the phrasing on the BSD license talks epxlicilty about source/binary code and software rather than written content.