anchor.diff:  ----
   dictionary Selector {
     DOMString type;
  -  optional any parameters;
  +  optional dictionary parameters;
   }
   ----
   
  
positive.code:   optional DOMString value;
  }
  ----
  
  
negative.code:   +fingerprint+
  
  Parameters type::
  [source, javascript]
  ----
  dictionary FingerprintParameters {
    DOMString[] fingerprints;
  }
  ----
  The fingerprints field contains hex values of SHA1 fingerprints of attestation
  certificates to match against.
  
  ===== x509Extension
  Match certificates by their extensions.
  