 }
 
 
-// MARK: - Private
+// MARK: - Private Constants
 //
 private extension Libxml2.Out.HTMLPrettyConverter {
 
     struct Constants {
 
+        /// List of 'Void Elements', that are expected *not* to have a closing tag.
+        ///
         /// Ref. http://w3c.github.io/html/syntax.html#void-elements
         ///
         static let voidElements = ["area", "base", "br", "col", "embed", "hr", "img", "input", "link",
                                    "meta", "param", "source", "track", "wbr"]
 
+        /// List of Boolean Attributes, that are not expected to have an actual value
+        ///
         /// Ref. https://opensource.apple.com/tarballs/libxml2/libxml2-8.tar.gz
+        ///
+        /// -   Source: HTMLTree.c 
+        /// -   Method: htmlIsBooleanAttr()
+        /// -   UsedBy: htmlAttrDumpOutput()
         ///
         static let booleanAttributes = ["checked", "compact", "declare", "defer", "disabled", "ismap",
                                         "multiple", "nohref", "noresize", "noshade", "nowrap", "readonly",

        return html
    }

    ///
    ///
    private func export(textNode node: TextNode) -> String {
        return node.text().escapeHtmlEntities().encodeUnicodeCharactersAsHexadecimal()
    }

    ///
    ///
    private func isVoidElementNode(elementNode node: ElementNode) -> Bool {
        return Constants.voidElements.contains(node.name)

            // No Op
        }

        /// Converts a Node into it's HTML String Representation
        ///
        func convert(_ rawNode: Node) -> String {
            return export(node: rawNode)
