Computer Configuration > Administrative Templates > Microsoft Edge
Both
HKLM\Software\Policies\Microsoft\Edge
Specifies URL patterns for sites that are allowed to request access to a serial port. If not configured, Microsoft Edge uses the value from the DefaultSerialGuardSetting policy (if set), or the user's settings. For unmatched sites, the following order applies: 1. 'SerialBlockedForUrls' (Block the Serial API on specific sites) (if matched). 2. DefaultSerialGuardSetting (if set). 3. User's settings. If URL patterns in this policy conflict with those in 'SerialBlockedForUrls', they will be ignored. For detailed information about valid url patterns, please see https://go.microsoft.com/fwlink/?linkid=2095322. Example value: https://www.contoso.com [*.]contoso.edu