User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624
Mozilla does not support Conditional Comments.
Conditional Comments is for example:
<!--[if expression]> HTML <![endif]-->
<p>Your are using the best browser :-)</p>
Steps to Reproduce:
Implementing this Microsoftism has been suggested before, and got little
support then. Marking as a duplicate.
*** This bug has been marked as a duplicate of 124751 ***