What does <# in HTML means?

I got the following HTML in PHP code:

    /* First part of a PHP script */
                <ul class="xyz cat-xyz-<?php echo $settings['post_id']; ?>">
                    var allTxt = settings.all_text;
                    var tax = settings.taxonomy;
                    print('<li class="abc abc-active">'+allTxt+'</li>');
                    print('<li class="abc">'+tax+' 1</li>');
                    print('<li class="abc">'+tax+' 2</li>');
    /* Rest of the PHP script */ 

Is this an error? If not - what does it do? It does not look like valid HTML or JS.