This.
If you were writing a script to mass-scan the web for vulnerabilities, you would want to collect as many http endpoints as possible. JS files, regardless of whether they're commented out or not, are a great way to find endpoints in modern web applications.
If you were writing a scraper to collect source code to train LLMs on, I doubt you would care as much about a commented-out JS file. I'm not sure you'd even want to train on random low-quality JS served by websites. Anyone familiar with LLM training data collection who can comment on this?