The Nikon D5 manual is now available for download (you can change the language on top of the page).
Nikon NEF Codec was also updated to version 1.28.0 for Windows 7 SP1/8/8.1/10 with added support for the Nikon D5 (see also this PDF on how to correct the display of NEF/NRW thumbnails in 64-bit Windows 7/Windows Vista).
Update – first Nikon D5 unboxing videos:
The first Nikon D5 cameras were already sold in Ireland: