What makes you think it isn't? I could be wrong, but my guess is that br is a function call and not a bareword literall. That function call is likely coming from CGI, which is xhtml compliant (which btw I thought had a space <br />).
Regarding br, for backwards-compatibility with browsers that are not XML-enabled, there must be a space before the /> (for example, <br />, not <br/>).
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