(2013-04-15) Bernard Vatant: This vocabulary defined in W3C namespace has absolutely no metadata, not even a title (the one put here is out of my hat, not sure it makes sense) or description. Put here for the record because it is linked from and to other W3C vocabularies.
(2013-08-24) Thomas Francart: Found some information (including a title : "Logic") on the "Semantic Web Application Platform" project page. (note that this project used other ontologies too, listed at http://www.w3.org/2000/10/swap/doc/CwmBuiltins). Advice : don't try to reuse unless you are a (semantic) web historian.