updated 'Secret Knowledge'

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -313,6 +313,7 @@ performance of any of your sites from across the globe.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="http://www.kegel.com/c10k.html"><b>The C10K problem</b></a> - it's time for web servers to handle ten thousand clients simultaneously, don't you think?<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://bankgradesecurity.com/"><b>Bank Grade Security</b></a> - when companies say they have "Bank Grade Security" they imply that it is a good thing.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://drawings.jvns.ca/"><b>Julia's Drawings</b></a> - some drawings about programming and unix world, zines about systems & debugging tools.<br>
+&nbsp;&nbsp;:small_orange_diamond: <a href="https://media.defcon.org/DEF%20CON%2026/"><b>DEF CON Media Server</b></a> - great stuff from DEFCON 26.<br>
 </p>
 
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