Differential ADC?

I've been reading the datasheet for the SAMD21, and in the ADC section (page 844) it says "The input selection is flexible, and both differential and single-ended measurements can be performed." Does this mean that it is a differential ADC? If so, has anyone created a library for this yet?

ATSAMD21 datasheet

Why would you want a library? There is nothing to do but put it into differential mode.