If set to true, a single instance of this component will run for all users. That instance will run as user 0, the default/primary user. When the app running is in processes for other users and interacts with this component (by binding to a service for example) those processes will always interact with the instance running for user 0. Enabling single user mode forces "exported" of the component to be false, to help avoid introducing multi-user security bugs. This feature is only available to applications built in to the system image; you must hold the permission INTERACT_ACROSS_USERS in order to use this feature. This flag can only be used with services, receivers, and providers; it can not be used with activities.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

[Android Documentation]