add historical update to the historical mirror note

2015/index.html

@@ -405,6 +405,12 @@ local compiler.</p>
 <h3 id="historical-note">Historical note:</h3>
 <p>The IOCCC has a website and now has a number of international mirrors.
 The primary website can be found at <a href="https://www.ioccc.org">www.ioccc.org</a>.</p>
+<h3 id="historical-update">Historical update:</h3>
+<p>The IOCCC website once had a number of
+<a href="https://web.archive.org/web/20201030210517/https://www.ioccc.org/mirror.html">international mirrors</a>.
+As of 2020 Dec 29, <a href="https://www.github.com">GitHub</a> serves as the distributed server farm for the
+<a href="https://github.com/ioccc-src/winner">IOCCC winner repo</a> that GitHub renders as
+<a href="https://www.ioccc.org">Official IOCCC web site - www.ioccc.org</a>.</p>
 <h2 id="remarks-on-some-of-the-winning-entries">Remarks on some of the winning entries</h2>
 <p>We believe you will again be impressed with this year’s winning entries.</p>
 <p>The fraction of worthy entries was higher than usual.</p>