Add unfiltered_html Capability to Admins or Editors in WordPress Multisite

add-unfiltered_html-capability-to-admins-or-editors.php

<?php

/**
 * Enable unfiltered_html capability for Editors.
 *
 * @param  array  $caps    The user's capabilities.
 * @param  string $cap     Capability name.
 * @param  int    $user_id The user ID.
 * @return array  $caps    The user's capabilities, with 'unfiltered_html' potentially added.
 */
function km_add_unfiltered_html_capability_to_editors( $caps, $cap, $user_id ) {

	if ( 'unfiltered_html' === $cap && user_can( $user_id, 'editor' ) ) {

		$caps = array( 'unfiltered_html' );

	}

	return $caps;
}
add_filter( 'map_meta_cap', 'km_add_unfiltered_html_capability_to_editors', 1, 3 );