Just another WordPress debug function

custom-setup.php

/**
 * Simple debug trace to the end of the page
 *
 * @usage d( $data );
 */

if ( true === WP_DEBUG ) {

	function d( $data ) {

		global $global_debug;
		$global_debug[] = $data;

  }

	function d_core() {

		global $global_debug;

		ob_start();

		print_r( $global_debug );

		$dump = htmlspecialchars( ob_get_contents() );

		ob_end_clean();

		printf( '<pre><code>%s</code></pre>', $dump );
	}

	add_action( 'wp_footer', 'd_core', 100 );
}