NepomukShow is a debugging tool which can be used to easily view nepomuk data. It currently resides in a scratch repo - git://anongit.kde.org/scratch/vhanda/nepomukshow
Using nepomukshow is fairly straightforward.
$ nepomukshow fileUrl or $ nepomukshow resourceUri
It has a bunch of additional options, which can be used to show extra info.
TODO: Improve this page!