Computer Configuration > Administrative Templates > Microsoft Edge > Content settings
Both
HKLM\Software\Policies\Microsoft\Edge
DEPRECATED: This policy is deprecated. It is currently supported but will become obsolete in a future release. This policy controls whether third-party storage partitioning is allowed by default. If this policy is set to 1 - AllowPartitioning, or unset, third-party storage partitioning will be allowed by default. This default may be overridden for specific top-level origins by other means. If this policy is set to 2 - BlockPartitioning, third-party storage partitioning will be disabled for all contexts. Use ThirdPartyStoragePartitioningBlockedForOrigins to disable third-party storage partitioning for specific top-level origins. This feature will be removed starting in Microsoft Edge version 145. To ensure compatibility, use the requestStorageAccess method instead. For more information, see https://developer.mozilla.org/en-US/docs/Web/API/Document/requestStorageAccess. Policy options mapping: * AllowPartitioning (1) = Allow third-party storage partitioning by default. * BlockPartitioning (2) = Disable third-party storage partitioning. Use the preceding information when configuring this policy.