User Configuration > Administrative Templates > Microsoft Outlook 2016 > Account Settings > RSS Feeds
User
HKCU\software\policies\microsoft\office\16.0\outlook\options\rss
This policy setting controls whether Outlook automatically makes an offline copy of the RSS items as HTML attachments. If you enable this policy setting, Outlook automatically makes an offline copy of RSS items as HTML attachments. If you disable or do not configure this policy setting, Outlook will not automatically make an offline copy of RSS items as HTML attachments.