Anyone know of good sources for this?
According to Road to VR the safari browser should support webxr content:
www.roadtovr.com
I found some content here:
Specifically interested in trying https://flowerbed.metademolab.com/
and https://wonderlandengine.com/dead-secret-circle-web/
According to Road to VR the safari browser should support webxr content:

Apple Vision Pro Will Support WebXR for Fully Immersive Experiences in the Browser
Apple has confirmed that Safari on Vision Pro will support WebXR, a web-standard that allows immersive experiences to be delivered through the browser. In a somewhat surprising move, Apple confirmed that Safari on Vision Pro will support WebXR. Prior to the reveal of the headset, it was an open...

I found some content here:

Immersive Web Developer Home
Get started building XR applications through the Web with the WebXR Device API, demos, docs, samples and more.
immersiveweb.dev
Specifically interested in trying https://flowerbed.metademolab.com/
and https://wonderlandengine.com/dead-secret-circle-web/