Improve fingerprinting sources intro.

    <title>Sources of Fingerprinting Issues</title>

    <para>

All fingerprinting issues arise from one of four primary sources in the

browser. Additionally, user behavior itself provides one more source of

potential fingerprinting. Listed in order from most severe to least severe in

terms of the amount of information they reveal, these sources are:

All browser fingerprinting issues arise from one of four primary sources:

end-user configuration details, device and hardware characteristics, operating

system vendor and version differences, and browser vendor and version

differences. Additionally, user behavior itself provides one more source of

potential fingerprinting.

    </para>

    <para>

In order to help prioritize and inform defenses, we now list these sources in

order from most severe to least severe in terms of the amount of information

they reveal, and describe them in more detail.

    </para>

    <orderedlist>

   </orderedlist>

  </sect3>

  <sect3 id="fingerprinting-defenses">

   <title>Fingerprinting defenses in the Tor Browser</title>

   <title>Fingerprinting Defenses in the Tor Browser</title>

   <para>

The following defenses are listed roughly in order of most severe