Found in Mouse Tools
Wire Cutter is for breaking or removing wire segments or entire wire nets.
Remove one segment: Click on a wire segment to remove just that one
straight wire segment.
Hold shift and click a wire segment to remove an entire wire net. The wire segment that was clicked, along with all other segments connected to it, recursively, are removed.
Click and drag in an blank area of the canvas to select a rectangular region in red. Any portions of wires passing through the selected region are removed.