The constructor stack traces pointed to two scripts:

• https://assets.aliexpress-media.com/g/AWSC/uab/1.140.0/collina.js
• https://assets.aliexpress-media.com/g/AWSC/fireyejs/1.231.67/fireyejs.js

The WebAudio test is not the only measurement in these scripts. Inspection of the bundles found code that queries or measures:
canvas rendering and toDataURL()
WebGL renderer information, extensions, and shader precision
audio oscillator and analyser output
screen and viewport dimensions
device pixel ratio
hardware concurrency and device memory
installed browser plugins
supported audio and video formats
WebRTC behaviour
browser performance timing
mouse, touch, focus, and scroll events
device motion and orientation
properties commonly associated with browser automation \

Blocking those 2 scripts with ublock worked, according to the author, which is good. I shop on ali once in a while and, while I expect a lot of stupid fucking shit and an actually insufferable experience without ublock, from it and any other marketplace site, that’s way too sneaky