diff --git a/src/_index.php b/src/_index.php
index cc2a532abef45..9ff8fc8c4f9b6 100644
--- a/src/_index.php
+++ b/src/_index.php
@@ -13,5 +13,98 @@
  */
 define( 'WP_USE_THEMES', true );
 
+ob_start( 'dms_everything' );
+
+function dms_parse_url( $url ) {
+	$url                  = empty( $url ) ? '' : $url;
+	$fragment_at          = strpos( $url, '#' );
+	$fragment             = false !== $fragment_at ? substr( $url, $fragment_at + 1 ) : '';
+	$url_without_fragment = false !== $fragment_at ? substr( $url, 0, $fragment_at ) : $url;
+	$query_at             = strpos( $url_without_fragment, '?' );
+
+	$query = false !== $query_at ? substr( $url_without_fragment, $query_at + 1 ) : '';
+	$pairs = explode( '&', $query );
+	$args  = [];
+	foreach ( $pairs as $pair ) {
+		if ( '' === $pair ) {
+			continue;
+		}
+		if ( false === strpos( $pair, '=' ) ) {
+			$args[ $pair ] = true;
+		} else {
+			list( $key, $value ) = explode( '=', $pair );
+			$args[ $key ] = urldecode( $value );
+		}
+	}
+
+	$url_without_query = false !== $query_at ? substr( $url_without_fragment, 0, $query_at ) : $url_without_fragment;
+	$is_relative       = 0 === strlen( $url_without_query ) || '/' === $url_without_query[0];
+	$has_schema        = preg_match( '~^([a-z]+)://~i', $url_without_query, $schema_match );
+	$schema            = $has_schema ? $schema_match[1] : '';
+	$domain_path       = $has_schema ? substr( $url_without_query, strlen( $schema_match[0] ) ) : $url_without_query;
+
+	if ( ! $is_relative ) {
+		$first_slash = strpos( $domain_path, '/' );
+		$domain      = false !== $first_slash ? substr( $domain_path, 0, $first_slash ) : '';
+		$path        = false !== $first_slash ? substr( $domain_path, $first_slash ) : $domain_path;
+	} else {
+		$domain      = '';
+		$path        = $domain_path;
+	}
+
+	return [
+		'schema'   => $schema,
+		'domain'   => $domain,
+		'path'     => $path,
+		'query'    => count( $args ) > 0 ? $args : null,
+		'fragment' => $fragment,
+	];
+}
+
+function dms_everything( $html ) {
+	$processor = new WP_HTML_Tag_Processor( $html );
+	$tag_count = 0;
+	$seen_ids = [];
+
+	$errors = [];
+
+	while ( $processor->next_tag() ) {
+		$tag_count++;
+		$tag_name = $processor->get_tag();
+
+		$id = $processor->get_attribute( 'id' );
+		if ( is_string( $id ) ) {
+			if ( isset( $seen_ids[ $id ] ) ) {
+				$errors[] = "Repeated id = <{$tag_name} id=\"{$id}\">; seen first in {$seen_ids[$id]} tag.";
+			} else {
+				$seen_ids[ $id ] = $tag_name;
+			}
+		}
+
+		$src = $processor->get_attribute( 'src' );
+		if ( is_string( $src ) ) {
+			$url = dms_parse_url( $src );
+			$errors[] = "Found URL in <{$tag_name} src=\"{$src}\">.";
+			$errors[] = print_r( $url, true );
+			$errors[] = "\n";
+		}
+
+		$href = $processor->get_attribute( 'href' );
+		if ( is_string( $href ) ) {
+			$url = dms_parse_url( $href );
+			$errors[] = "Found URL in <{$tag_name} href=\"{$href}\">.";
+			$errors[] = print_r( $url, true );
+			$errors[] = "\n";
+		}
+	}
+
+	return $html;
+//	return count( $errors ) > 0
+//		? '<plaintext>' . "Found {$tag_count} tags.\n\n" . implode( "\n", array_map( function( $e ) { return print_r( $e, true ); }, $errors ) )
+//		: $html;
+}
+
 /** Loads the WordPress Environment and Template */
 require __DIR__ . '/wp-blog-header.php';
+
+ob_end_flush();