Add a warrant canary

canary.txt

+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA512
+
+BioTorrents.de positively confirms that the integrity of our system is sound:
+all our infrastructure is in our control, we have not been compromised or
+suffered a data breach, we have not disclosed any private encryption keys, and
+we have not been forced to modify our system to allow access or information
+leakage to a third party.
+
+Date:	2020-01-15
+Key:	760EBED7CFE266D7
+
+-----BEGIN PGP SIGNATURE-----
+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+=0HIZ
+-----END PGP SIGNATURE-----

design/privatefooter.php

   <div id="disclaimer_container" class="thin" style="text-align: center; margin-bottom: 20px;">
     None of the files shown here are actually hosted on this server. The links are provided solely by this site's users. These BitTorrent files are meant for the distribution of backup files. By downloading the BitTorrent file, you are claiming that you own the original file. The administrator of this site (<?=site_url()?>) holds NO RESPONSIBILITY if these files are misused in any way and cannot be held responsible for what its users post, or any other actions of it.
   </div>
-  <div class='thin'><a href='/canary.php'>Warrant Canary</a></div>
+  <div class='thin'><a href='/canary.txt'>Warrant Canary</a></div>
 <?
   }
   if (count($UserSessions) > 1) {