I'm confused by the relation of this specification with the PBF one:
http://wiki.openstreetmap.org/wiki/Pbf

The confusion arises by the fact that mapnik-vector-tile refers to these specs as "vector tile" (https://github.com/mapbox/mapnik-vector-tile#implementation-details) but then have a "vector tile reader" that only supports PBF:
https://github.com/mapbox/mapnik-vector-tile/tree/master/examples/c%2B%2B

Are them the same format ? Different formats sharing the same extension ?