[1] [MS-WMSP]: user-public ( 版) <https://msdn.microsoft.com/en-us/library/cc251266.aspx>
This directive specifies that if the cache is not acting as a proxy server, the content MAY be cached and MAY be shared with other users on the device on which the client software is running. If the cache is not acting as a proxy server, this directive overrides the private (section 2.2.1.1.4) directive.