public String getHeader(String name) {
        return getRequestDetails().getHeader(name);
    }
Returns the value of the HTTP header having the given name from the
original details of the HTTP request that is related to these
credentials. Header names are case-insensitive. If no such header was
present, null is returned. If the header had multiple values, the first
value is returned.
<p>
For access to all values of a header, as well as other details of the
request, see {@link #getRequestDetails()}. This is a convenience
function that is equivalent to invoking {@link RequestDetails#getHeader(java.lang.String)}.

@param name
    The name of the header to retrieve. This name is case-insensitive.

@return
    The first value of the HTTP header with the given name, or null if
    there is no such header.
guacamole-ext/src/main/java/org/apache/guacamole/net/auth/Credentials.java