Popular public copyright licenses like GPL3, MIT, Apache2, CC-BY-SA3, etc. have official human-readable texts, and, I suppose, in nowadays, have also translations to "machine-readable texts", that are REL interpretations/translations of the official texts... Each license is a set of clauses that can be described by REL, and this set is my interest.
There are a "license database" (or catalog or content with semantic markup) with each license translated to REL or RDF?
NOTES
Existing translations and samples. The only that I found was a CC licenses translated to CC-REL.
"REL is RDF". Any REL (Rights Expression Language), ex. CC-REL or RightsML, can be translated to RDF, so we can suppose that any popular license tranlated to REL, is a RDF descriptor of the license.
"RDF is JSON-LD, RDFa, Microdata", no problem for me, all can be translated to another.
"catalogues". They exist, as Wikipedia lists, OKFN lists, tldrlegal lists, and others... But no one have a REL or RDF translation/interpretation.
In Doncel et al (http://delicias.dia.fi.upm.es/~vrodriguez/pdf/2014.11.jurix.dataset.pdf) the authors describe a catalog of licenses translated into RDF.
You can find it here: http://rdflicense.linkeddata.es/, along with a link to download it. I have tried and each of the URIs are derreferenceable (although they might take a little to load), pointing you to the original page of the license. The catalog is described using standard models, such as dublin core or ODRL.