"Leather trimmings" refer to small decorative or functional elements made from leather that are added to enhance the appearance or usability of an item. Full definition
Each premium package comes with the optional safety features and various conveniences like a power sunroof and heated seats with leather trim. (carbuzz.com)
The rich charcoal color is accented with black leather trim, including a convenient handle. (potterybarn.com)
But I think the faux leather trim on the leggings, the studded clutch, and the boots give a bit of edge to my comfy look. (fashionshouldbefun.com)