This link broke, but I found a replacement that is actually more in line with the other references in that section (in that it uses the ShowIssue facility on www.dwarfstd.org).
Applied. Gerald Index: changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.7/changes.html,v retrieving revision 1.145 diff -u -r1.145 changes.html --- changes.html 28 Dec 2016 23:42:42 -0000 1.145 +++ changes.html 3 Mar 2017 10:06:00 -0000 @@ -997,7 +997,7 @@ value</a> and <a href="http://www.dwarfstd.org/ShowIssue.php?issue=100909.2">call site</a> information, <a - href="http://www.dwarfstd.org/doc/040408.1.html">typed DWARF stack</a> + href="http://www.dwarfstd.org/ShowIssue.php?issue=140425.1">typed DWARF stack</a> or <a href="http://www.dwarfstd.org/ShowIssue.php?issue=110722.1">a more compact macro representation</a>. Support for these extensions