Computer Configuration > Administrative Templates > Microsoft Edge
Both
HKLM\Software\Policies\Microsoft\Edge
For security reasons, the showOpenFilePicker(), showSaveFilePicker() and showDirectoryPicker() web APIs require a prior user gesture ("transient activation") to be called or will otherwise fail. If you enable this policy, admins can specify origins on which these APIs can be called without prior user gesture. For detailed information on valid url patterns, please see https://go.microsoft.com/fwlink/?linkid=2095322. * is not an accepted value for this policy. If you disable or don't configure this policy, all origins will require a prior user gesture to call these APIs. Example value: https://www.example.com [*.]example.edu