Index: src/wp-admin/includes/class-wp-site-icon.php
===================================================================
--- src/wp-admin/includes/class-wp-site-icon.php	(revision 45458)
+++ src/wp-admin/includes/class-wp-site-icon.php	(working copy)
@@ -59,6 +59,15 @@
 		 */
 		180,
 
+		/**
+		 * Add support of new sized for Google webmaster documentation. 
+		 * 
+		 * See https://support.google.com/webmasters/answer/9290858
+		 */
+		48,
+		96,
+		144,
+		
 		// Our regular Favicon.
 		32,
 	);
Index: src/wp-includes/general-template.php
===================================================================
--- src/wp-includes/general-template.php	(revision 45458)
+++ src/wp-includes/general-template.php	(working copy)
@@ -3020,6 +3020,18 @@
 	if ( $icon_32 ) {
 		$meta_tags[] = sprintf( '<link rel="icon" href="%s" sizes="32x32" />', esc_url( $icon_32 ) );
 	}
+	$icon_48   = get_site_icon_url( 48 );
+	if ( $icon_48 ) {
+		$meta_tags[] = sprintf( '<link rel="icon" href="%s" sizes="48x48" />', esc_url( $icon_48 ) );
+	}
+	$icon_96 = get_site_icon_url( 96 );
+	if ( $icon_96 ) {
+		$meta_tags[] = sprintf( '<link rel="icon" href="%s" sizes="96x96" />', esc_url( $icon_96 ) );
+	}
+	$icon_144 = get_site_icon_url( 144 );
+	if ( $icon_144 ) {
+		$meta_tags[] = sprintf( '<link rel="icon" href="%s" sizes="144x144" />', esc_url( $icon_144 ) );
+	}
 	$icon_192 = get_site_icon_url( 192 );
 	if ( $icon_192 ) {
 		$meta_tags[] = sprintf( '<link rel="icon" href="%s" sizes="192x192" />', esc_url( $icon_192 ) );