From what I can tell the $list_box_contents array is a multidimensional array used to piece together the html for displaying the list of products using variables that are set according to the preferences set up in admin for displaying products.
Maybe you could find some more pieces to your puzzle here:
\includes\modules\product_listing.php
PHP Code:
00019: $list_box_contents[0] = array('params' => 'class="productListing-rowheading"');
00068: $list_box_contents[0][$col] = array('align' => $lc_align,
00081: $list_box_contents[$rows] = array('params' => 'class="productListing-even"');
00083: $list_box_contents[$rows] = array('params' => 'class="productListing-odd"');
00086: $cur_row = sizeof($list_box_contents) - 1;
00174: $list_box_contents[$rows][$col] = array('align' => $lc_align,
00189: // $list_box_contents[$rows][] = array('params' => 'class="' . $list_box_description . '" colspan="' . $zc_col_count_description . '"',
00196: $list_box_contents = array();
00198: $list_box_contents[0] = array('params' => 'class="productListing-odd"');
00199: $list_box_contents[0][] = array('params' => 'class="productListing-data"',