If true, HTML Purifier will sort attributes by name before writing them back to the document, converting a tag like: <el b="" a="" c="" /> to <el a="" b="" c="" />. This is a workaround for a bug in FCKeditor which causes it to swap attributes order, adding noise to text diffs. If you're not seeing this bug, chances are, you don't need this directive.
<el b="" a="" c="" />
<el a="" b="" c="" />