I have a feeling it might be talking of things as below, which are fitted on the surrounds, or in the front of appliances.
TrimKits USA
www.trimkitsusa.comCustom Microwave Trim Kits Let TrimKits USA precisely craft a custom trim kit to work with your microwave, microwave drawer, coffee maker, steam/speed oven and wall ...
General Electric Wall Oven Trim - AppliancePartsPros.com
www.appliancepartspros.com › … › GE Wall Oven Parts › Trim
Buy today - ships today. Over 2.1 million appliance parts in stock. Original, high quality General Electric Wall Oven Trim parts with fast shipping and award winning ...
Oven Filler Strips - Micro-Trim, Inc.
www.microtrim.com/fillerstrips.htmMicro-Trim Custom Trim Kits make it possible to install almost any model of built-in microwave, cooktop, or wall oven into an existing opening.