Adjust Trim
shortcut DA in edit mode
shortcut DA + CTRL scroll to change a Trim
check out the hints in the tool's modal HUD for more
Just as the Adjust Decal tool enables you to do manipulate Decal objects, the Adjust Trim tool allows you to manipulate Trims.
Trims in this context are face selections, that are unwrapped to a specific part of a Trim Sheet and that have assigned a Trim Sheet Material.
Selection
Some faces, that have a Trim Sheet Material assigned