There is a WebXR rubric on the homepage of three.js (here: https://threejs.org/examples/).
There are 3 examples i wanted to test:
https://threejs.org/examples/#webxr_ar_cones
https://threejs.org/examples/#webxr_ar_hittest
https://threejs.org/examples/#webxr_ar_paint
All of them showing me a hint, that i have to enable something in chrome settings, what i already did.
My Chrome version: 79.0.3945.117
Edit: I just saw the (80+) hint… nevermind.