Change custom_logo Schema markup

change-custom-logo-schema-markup.php

/**
 * Use one of the filters. Not multiple...
 * I'd use the third.
 */

add_filter( 'wp_get_attachment_image_attributes', function ( $attr ) {
	if ( isset( $attr['class'] ) && 'custom-logo' === $attr['class'] ) {
		$attr['itemprop'] = 'image';
	}

	return $attr;
} );


add_filter( 'get_custom_logo', function() {
	$custom_logo_id = get_theme_mod( 'custom_logo' );
	$html           = sprintf( '<a href="%1$s" class="custom-logo-link" rel="home" itemprop="url">%2$s</a>',
		esc_url( home_url( '/' ) ),
		wp_get_attachment_image( $custom_logo_id, 'full', false, array(
			'class'    => 'custom-logo',
			'itemprop' => 'image',
			'alt'      => '',
		) )
	);

	return $html;
});

/**
 * Fix Google Schema error, "The property logo is not recognised by Google for an object of type WPHeader".
 * 
 * @author  Mike Hemberger, Gary Jones
 * @param   string  $html  The logo HTML.
 * @return  string  The modified HTML.
 */
add_filter( 'get_custom_logo', function( $html ) {
	return str_replace( 'itemprop="logo"', 'itemprop="image"', $html );
});

Or this:

/**
 * Fix Google Schema error, "The property logo is not recognised by Google for an object of type WPHeader".
 *
 * @param   string  $html  The logo HTML.
 *
 * @return  string  The modified HTML.
 */
add_filter( 'get_custom_logo', function( $html ) {
	$html = str_replace( 'itemprop="logo"', 'itemprop="image"', $html );
	return $html;
});