Autonomous sensory meridian response.
In other words, they play sounds or scenarios (role playing etc...) that people who are having trouble sleeping watch. After watching/listening to the repetition, it hits their senses and helps them sleep. Things such as whispering or even keyboard strokes, and mindless monotone talking can be considered ASMR.
People make and upload these videos to YouTube, good ones will get a lot of hits from people who have trouble sleeping (and the uploader can make revenue if they monetise the video).
The fuck someone can think listening to a chewbacca munching on an apple is relaxing is beyond me!