I also didn't understand their purpose so I grabbed these and plugged them
4Runner Lifestyle Fender Inserts for 4Runner (2025-Current) https://share.google/WTISEZ99Hu7gglZtV
Another +1 for Sherpa Capitol here. Easy install, no drill, no silicone, lots of options for customizations with the crossbar placement, and two fairing options for light bar/no light bar.
I purchased these same lights but had a different issue, the pigtail connector from the Roof Wire would not disconnect now matter what I tried (pushed the tab, tried flathead, etc. - something was wrong b/c every video was a simple pinch, then disconnect).
The connector ended up snapping, and...