The sphere trace visibility? I noticed others were mentioning it. All that’s needed there (and I think the video creator may have cut this part) is to enable the Draw Debug Type set to For Duration. I wouldn’t run the checks on tick, just sequentially when the button is pressed or when holding directionals while climbing.
You could also take a look at how the new Gameplay Animation Sample Project handles ledges, as this is also rather close to the industry standard, though it is replicated and based on the new motion tools.