In my (new) EASA licence, it's actually entered as a rating so yes, it is a rating and not a qualification, as far as EASA goes.
With regards training, I think every flight school will do it slightly differently, when I did mine, we first spent an hour on ground school, discussed things such as human factors as it pertains to eyesight, especially the impact of fixing your sight on a stationary point, loss of night vision due to hypoxia or sudden bright lights (Pax taking flash pictures), legal requirements for a night flight, filing IFR flight plans, the black hole phenomena - in particular when flying to NVFR airfield with nominal lighting - and so forth.
Then the obligatory circuit training - 5 with the instructor, 5 solo (always full stop, no touch and go) followed by night navigation which basically covered VOR radials and the like (no NDBs cos there weren't any in the area) and a 3 hour cross country flight.
Was good fun and I'm hoping New Year's Eve will be a good night for flying, the moon will be nearly full and I'm planning to fly above the Ruhr Valley, videoing the fireworks going off below.....