Try dashboard buttun - what is it?

Hello!
what is this button for?
image

When I try open it, I redirect to /dashboard/fail-whale with Error caption and only one button “Reload”.
Reload returns me to main page.

From https://github.com/rancher/rancher/releases/tag/v2.4.0:

Preview next-gen UI: The next generation Rancher UI is available in preview mode at the cluster view level. The new Rancher UI provides navigation based on native Kubernetes namespaces. Rancher projects are still available to the end-user for managing attributes across multiple namespaces. A YAML editor provides a way to edit all Kubernetes objects with field suggestions based on OpenAPI specs. Note: This is not supported in an air gap environment while it’s still experimental.

Well, that doesn’t work…circle animation loading forever.