Till Feb 2nd, the Legion Archaeology mount Spirit of Eche’ro is available by starting a quest chain in Dalaran: The Right Path, given out by Dariness the Learned. This quest is only available for 2 weeks every 6 months, following the Legion Archaeology quest rotation.
The quest leads you to Laying to Rest, which requires you to survey digsites in Highmountain until you acquire 600x Bone Fragment of Eche’ro. Each survey in a Highmountain digsite awards you up to 5x Bone Fragment of Eche’ro.