Open 0xr.space or the Model Explorer app and press Scan, the round control in the middle of the dock. On the page the camera opens with the line Point the camera at a QR code. A button shows when it is in view. When a code is in view a chip names it, Shared model or Gallery model, with an Open button; press it and the model opens. Inside a headset session, press Scan and look at the code, and a shared or gallery model opens by itself.
On the page nothing opens without your press. Another web link shows its address and Open, which goes to a new tab, and plain text shows Copy. On a Quest 3 in a session, Scan also starts the object scan with its boxes; on other headsets a press with no code in view takes a photo you can make into a 3D model with Photo → 3D. The camera needs permission, and on Quest that includes Headset cameras.
It reads any code, but only shared and gallery models open in Model Explorer. Other web links open in a new tab when you press Open, and text can be copied.
The camera permission is missing. In the Quest app the dialog needs Headset cameras ticked; for the Quest browser, turn on Headset cameras for Browser in the headset's permission settings.
Hold the camera closer so the code fills more of the view, keep it flat and still, and add light. A code on a bright screen reads better with the screen brightness turned down a little.
See the privacy page at https://0xr.space/privacy/ for what the camera features send and keep.