Episode 3 - PHP Output Buffer Basics

markup.php

add_filter( 'the_content', __NAMESPACE__ . '\add_markup_to_content' );
function add_markup_to_content( $content ) {

	$html = '<div class="entry-content-container" itemprop="text"><div class="wrap">';
	$html .= $content;
	$html .= '</div></div>';

	return $html;
}