How to best handle modification notices and notices of origin in SPDX
recently I’ve been thinking about how to store¹ additional notices that are required by some licenses on the SPDX license list. Specifically reference to the origin of the work, and notice of modification of original work.
I’m sure people on this list are very well aware of the notice of modification as e.g. in §5.a of GPL-3.0:
“The work must carry prominent notices stating that you modified it, and giving a relevant date.”
As an example of where the requirement (of attribution) is to provide a notice of where the original work came from, I can offer CC-BY-4.0 and its §3.a.1.A.v:
“a URI or hyperlink to the Licensed Material to the extent reasonably practicable;”
…which BTW also includes a notice of modification requirement in §3.a.1.B:
“indicate if You modified the Licensed Material and retain an indication of any previous modifications;”
This “BY” clause is inherent to all CC-* licenses (apart from CC0-1.0 and CC-PDDC), and similar clauses exist already in its 1.0 version, so I think it is safe to assume that all CC licenses have this requirement.
So, I was wondering if there was a way to express this information in SPDX (other than the generic comment).
I thought of some ugly workarounds, but would first like to hear if there is already a proper way, before I soil this mailing list with that.
1 Or, better yet, express.