It is more repetitive and atmospheric than vaporwave, and not danceable like future funk. Some tracks may have an overlay of ambient ‘mall’ sound effects (people talking, announcements over a loudspeaker, various noises associated with shopping) to simulate a mall space.

A sample or original composition is looped, and manipulated to sound as if it’s been recorded in a physical mall (echo-y, sometimes tinny sound). It’s not abrasive or attention-grabbing like some vaporwave, and there is a limited amount of chopping and screwing. It’s meant to be more background noise, and can elicit both feelings of unsettlement and nostalgia.

Further reading:

Atmospherics as a marketing tool (Philip Kotler / 1973) – PDF
Modelling the shopping soundscape (Journal of Sonic Studies)
Interactive sound strategy enhances shopping mall experience (Architecture & Design)
How Shopping Malls can go from blasting music to quiet shopping (Elevating Sound)
Strategic shopping centre design (Choice)
The Shopping Mall’s Socialist Pre-History (Sam Withered
www.moodmedia.com
en.m.wikipedia.org/wiki/Muzak_(brand)
en.m.wikipedia.org/wiki/Elevator_music
www.press.umich.edu/script/press/8718

archive.org/details/attentionkmartshoppers