I built a clickable concept index for long YouTube coding tutorials

The problem I watch a lot of long coding tutorials on YouTube — 2, 3, sometimes 4 hours. React, Node, full-stack builds. The problem: I always need to go back and find a specific part. "Where did he set up the auth context?" or "When did she configure the middleware?" Every time, it's 5 minutes of scrubbing through the progress bar trying to find the right moment. YouTube chapters help sometimes, but they're broad ("Part 3: Backend") — not specific enough when you need the exact moment a concept