Removed from new Dell XPS 13 laptop 27th June 2017 when replaced by 1Tb so actually unused except at the factory install. I hope this is correct - hard to get info from the web on this.
PcI e Gen 3 4 lanes. I believe the m.2 socket is a 2280
Has not been wiped as I didn't wish to do any damage. Easily done when imaged or new Windows or Mac.