User Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Trust Center > Trusted Catalogs
User
HKCU\software\policies\microsoft\office\16.0\wef\trustedcatalogs\catalog02
This policy setting sets the URL location of a Trusted SharePoint Catalog or Shared Folder Catalog. All web add-ins at this location are trusted so that users can work with these add-ins in their documents. However, the user cannot insert these add-ins into an Office document. If you enable this policy setting and set the URL, users can work with web add-ins from the SharePoint Catalog or Shared Folder Catalog at that URL. Shared Folder Catalogs at that URL will be ignored if the policy to allow users to control the Trusted Shared Folder Catalogs is enabled. If you disable this policy setting, users will not be able to work with any web add-ins on Internet zone catalogs, and they will be prompted before they start web add-ins from any other catalogs. If the policy to allow users to control the Trusted Shared Folder Catalogs is enabled, users can set their own Trusted Shared Folder Catalog locations and web add-ins in the their Trusted Catalogs locations will be started without a trust prompt. If you do not configure this policy setting or any other policy settings in the Trusted Catalogs folder, users can set their own Trusted Sharepoint Catalog and Shared Folder Catalog locations