Each Matter Fabric is cryptographically isolated from the others: Apple Home cannot see the automations configured in Google Home on the same device, which guarantees confidentiality between competing ecosystems.

Fabric isolation is enforced at multiple layers: each Fabric has its own certificate chain, CASE sessions are scoped per Fabric, Bindings and Group keys are also per-Fabric, and the ACL on the device prevents cross-Fabric attribute reads unless an explicit shared scope is configured. The practical consequence is that Apple has no visibility on the fact that Google or Amazon are also controlling the same physical device, which matters both for end-user privacy and for the antitrust posture of the standard.

Do not try to debug a multi-admin issue by reading state from "the other" Fabric: by design you cannot, and any tool that claims otherwise is either using a vendor-specific backdoor or breaking the spec.