The debug output produces html validator errors, caused by two attributes that are not separated by a space. The fix is just to add a space at the beginning of $identifierText, like this:

Index: lib/ezutils/classes/ezdebug.php
===================================================================
— lib/ezutils/classes/ezdebug.php (revision 20604)
+++ lib/ezutils/classes/ezdebug.php (working copy)
@@ -1426,7 +1426,7 @@
if ( !$hasLevel[$debug['Level']] )

{ $hasLevel[$debug['Level']] = true; - $identifierText = 'id="' . $outputData['xhtml-identifier'] . '"'; + $identifierText = ' id="' . $outputData['xhtml-identifier'] . '"'; }

$color = $outputData["color"];
$name = $outputData["name"];

Steps to reproduce

In firefox web developer, validate the debug with Tools -> Validate local HTML.