User Configuration > Administrative Templates > Microsoft Project 2016 > Project Options > View > Show
User
HKCU\software\policies\microsoft\office\16.0\ms project\options\view
Displays the indicator for OLE linked objects in the lower-right corner of the cell that contains the link. If you enable this setting, the indicator is displayed for OLE linked objects. If you disable or do not configure this setting, the user's default setting is used.