Preserved HTML Editor Markup Plus is a free WordPress plugin designed for seamless HTML editing in the TinyMCE editor. This tool uniquely allows developers to edit HTML while end-users can simultaneously utilize the WYSIWYG Visual tab without losing formatting. Unlike other plugins, it ensures that the HTML markup remains intact, preventing distortion when switching between editing modes. The plugin is especially beneficial for collaborative environments where both developers and content editors work concurrently.

To ensure proper functionality, users must carefully follow the installation instructions provided, particularly if they have existing content. The plugin also introduces support for HTML5 Block Anchor tags and other HTML5 elements, filling a gap in current WordPress capabilities. This enhancement makes it a valuable addition for those looking to maintain HTML integrity while working within the WordPress framework.