You can find that property in System properties list (sys_property.list), whose default value is empty. But this property is different, see below description.
"A list of comma separated attachment mime types that do not render inline in the browser. This will prevent cross site scripting attacks. For example, text/html will force html files to be downloaded to the client as attachments rather than viewed inline in the browser."
No, other than PDF files which is opened in separate pop up window, you cant read .docs directly. They have to be downloaded.
I recommend, please raise a enhancement request from "Hi" and will be implemented accordingly.
PS: Hit like, Helpful or Correct depending on the impact of the response
Thanks
Naveen
