This is the lens mount for Fujifilm’s X-series mirrorless cameras. These include the Fujifilm X-T2, X-H1, X-E3 and others. Any X-mount lenses can be used on any X-mount camera, though note that Fujifilm’s medium format GFX 50S uses a different mount and different lenses.
A sensor layout unique to Fujifilm which replaces the usual bayer pattern of red, green and blue photosites with a more ‘random’ arrangement. Fujifilm says this eliminates the need for a low-pass filter to combat moiré (interference) effects, resulting in sharper fine detail.
An extra-fast memory card format currently used only in the Nikon pro DSLRs. It’s about half the size of Compact Flash but has the potential for extremely high speeds – though it’s yet to be seen whether many other camera makers will adopt it.