2020-05-11 UTC
# 
[KevinMarks] I think the discussion is on the wiki. The point of rels was to collate the links by type, so you could find all the rel=me or whatever. The point of rel-urls was to find all the rels that apply to a single link without having to walk all the rels. As the parser is walking all of the links with rels anyway, it can build these and save the consumer time and effort.