That is the lock mechanism. It serves as the anti-billow device when the slide is in while your traveling. If wind gets under the topper it stops it from unrolling by resting against a bracket on the RV's wall. You don't want to travel without it.
You will have to contact A&E Dometic for replacement.
Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989, seasonal since 2000
Car Shredder Op/Tech, Scrap Metal Recycling - retired
The Faster I Go, The Behinder I Get.