Gigabyte's packaging for the Z270N-Gaming 5 is as diminutive as the product itself. Despite that, Gigabyte manages to cram a whole raft of information onto the box pointing out its key selling points such as RGB lighting, Intel AC WiFi and USB 3.1.
The accessory bundle is unsurprisingly basic. It includes just two SATA cables, discs and documentation, a rear I/O shield and the WiFi Antennae. In short, it's sufficient for a motherboard of this size and calibre.
Just bought this board (2017-07) and without issuing a notice or a revision number change, it appears they have fixed the m.2 issue. I installed a Samsung EVO m.2 drive, and a Corsair H60 backplate, and there was plenty of room between the two. Matched the placement I’ve seen in pictures from other boards like the z270 WiFi from gigabyte. Cheers