This adds support for webp when importing webp images into WordPress. [datafeedr]

add-webp-to-wordpress.php

<?php

/**
 * Add support for webp to WordPress.
 * 
 * @param array $mime_types
 *
 * @return array Updated $mime_types array.
 */
add_filter( 'mime_types', 'mycode_mime_types', 20 );
function mycode_mime_types( $mime_types ) {

	if ( isset( $mime_types['webp'] ) ) {
		return $mime_types;
	}

	$mime_types['webp'] = 'image/webp';

	return $mime_types;
}