What is a "top cap" on a climber's haul bag and how does it work? In Mountaineering: The Freedom of the Hills (and also at neilhopkins.us/mountaineering-guide-2/aid-climbing-equipment) is
A top cap to the haul bag is a good idea to protect the knot connecting the sack to the haul line and help reduce snagging problems while hauling.
but there is no diagram. I can imagine what it looks like because of
An effective top cap can be readily fashioned from an empty 2-liter plastic bottle.
Is the sequence like this, from bottom going up: haul sac, strap, carabiner, knot, (upright) "top cap", then haul rope, with the rope going through the small opening of the bottle?