If provided, this is the trigger indicating that the searchable activity provides suggestions as well. The value must be a fully-qualified content provider authority (e.g. "com.example.android.apis.SuggestionProvider") and should match the "android:authorities" tag in your content provider's manifest entry. Optional attribute.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

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]