Computer Configuration > Administrative Templates > Microsoft Edge
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 is deprecated, use the ''WindowOcclusionEnabled' (Enable Window Occlusion)' policy instead. It won't work in Microsoft Edge version 92. Enables native window occlusion in Microsoft Edge. If you enable this setting, to reduce CPU and power consumption Microsoft Edge will detect when a window is covered by other windows, and will suspend work painting pixels. If you disable this setting Microsoft Edge will not detect when a window is covered by other windows. If this policy is left not set, occlusion detection will be enabled.