Cured Leather is a resource for repairing leather footwear, gloves, and accessories. It can be found uncommonly in containers or on the ground, and can be harvested from leather items. It is unrelated to the hides obtained from harvesting animals.
Cured Leather is harvested from and used to repair:
In early builds of The Long Dark (alpha), Deer Hides provided "Fresh Leather" when harvested; this item could be converted into "Cured Leather" by curing it, and then used for repairing clothing. Cured Leather is still present in The Long Dark, but is only obtainable by Harvesting leather footwear, gloves, the Moose-Hide Satchel, and Beachcombing.