simulated GATT service is a Bluetooth cache

Author: chengweih001

index.bs

@@ -5014,8 +5014,8 @@ may have associated properties like <a>Manufacturer Specific Data</a> and <a>Ser
 and has a <dfn>simulated GATT service mapping</dfn>, which is an <a>ordered map</a> of Bluetooth
 <a>UUID</a> {{strings}} to <a>simulated GATT services</a>.
 
-A <dfn>simulated GATT service</dfn> is a software defined [=Service=] that belongs to a
-<a>simulated Bluetooth device</a>, and has a property of <a>UUID</a>.
+A <dfn>simulated GATT service</dfn> is a software defined and known-present <a>Bluetooth cache</a>
+of [=Service=] that belongs to a <a>simulated Bluetooth device</a>, and has a property of <a>UUID</a>.
 
 Issue: CDDL snippetes use the "text" type instead of
 "browsingContext.BrowsingContext" to allow indepedent programmatic