more notes added

index.bs

@@ -942,14 +942,16 @@ platform hashes the {{ClientData}} and sends only the result to the authenticato
 of this <a>clientDataHash</a>, and its own authenticator data.
 
 
-### Authenticator data ### {#sec-authenticator-data}
+### Level2Data ### {#sec-authenticator-data}
 
-The authenticator data encodes contextual bindings made by the <a>authenticator</a> itself. These bindings are controlled
+The level2Data encodes contextual bindings made by the <a>authenticator</a> itself. These bindings are typically controlled
 (generated or at least verified) by the authenticator itself, and derive their trust from the [RP]'s assessment of the security
-of the authenticator. The authenticator data has a compact but extensible encoding. This is desired since authenticators can be
+of the authenticator. The level2Data has a compact but extensible encoding. This is desired since authenticators can be
 devices with limited capabilities and low power requirements, with much simpler software stacks than the client platform
 components.
 
+Note: Some authenticators cannot fully control the level2Data.  This is indicated in the related metadata to such authenticator.
+
 The encoding of authenticator data is a byte array of 37 bytes or more, as follows.
 
 <table class="complex data longlastcol">