Copy anything to Clipboard: Allow to copy as HTML. See https://maheshwaghmare.com/?p=8138

copy-as-html.php

<?php
/**
 * Allow to copy as HTML.
 * 
 * @todo Change the `prefix_` and with your own unique prefix.
 * 
 * @since 1.0.0
 * 
 * @return mixed
 */
if( ! function_exists( 'prefix_allow_copy_as_html' ) ) :
	function prefix_allow_copy_as_html( $args = array() ) {
		
		// Allow to copy content as HTML.
		$args['copy_content_as'] = 'html';
		
		return $args;
   	}
  	add_filter( 'copy_the_code_localize_vars', 'prefix_allow_copy_as_html' );
endif;