I was curious: https://www.thecut.com/2014/08/sleep-hack-keep-one-foot-outside-your-covers.html

TL; DR: Our bodies cool down when sleeping, feet can help regulate temeprature, so we may be able to initiate sleep better/quicker using our feet to cool down.

There is no study in the article; it’s speculation by “Natalie Dautovitch, a spokesperson for the National Sleep Foundation and a psychology professor at the University of Alabama”.

This also works surprisingly well. Once it actually runs… It can be quite buggy.

https://github.com/KieronQuinn/AmbientMusicMod (It’s for Android and requires Shizuku (https://shizuku.rikka.app/)).