To nitpick: It's not scraping, the youtube.com undocumented api changes all the time, in my tinfoil view probably to mess with things like youtube-dl and 3rd party apps.
Please explain.
YT constantly changes how it masks access to the underlying resources with JS updates that break these libraries. The most frequent updates are to fix this.
Verbatim from my comment: "the youtube.com undocumented api"
Thanks for reading.
In fact I'm pretty sure I've seen youtube-dl mention downloading the HTML page when using it with YouTube, so maybe it does even scrape YouTube.