In visionOS 26 (with Website Environments enabled), there was a two step action to enable the environment: click button on the left of the address bar (1 in image), then click "Open Website Environment" (2 in image).
This example was shown again this year in Build next-generation experiences with visionOS 27.
But I do no see this working in visionOS 27. Instead, I've needed to add a button for the user to open (and optionally close) the website environment.
Is adding a button/control to the web page the new way to activate website environments?