Bontrager has released a new XR 3, basics a RockRazor, Slaughter etc concept: side knobs from Xr4, center from XR 2. Right know only in XR casing and 29x2.4 and 27.5x2.8, but with such disparate sizes and their commitment to the 29+ sizes, I bet more sizes will follow. Hopefully also a SE casing. I really want a 29x2.6 for my bike.
For now, the XR3 27.5x2.8 will be great option for local XC rides on my wife’s 27.5 plus bike: fast, Light and plenty grippy.