update_network_option_new_admin_email

		'page',
		'comments',
		'blog',
		'files',
		'feed',
		'wp-admin',
		'wp-content',
		'wp-includes',
		'wp-json',
		'embed',
	);

	/**
	 * Filters reserved site names on a sub-directory Multisite installation.
	 *
	 * @since 3.0.0
	 * @since 4.4.0 'wp-admin', 'wp-content', 'wp-includes', 'wp-json', and 'embed' were added
	 *              to the reserved names list.
	 *
	 * @param string[] $subdirectory_reserved_names Array of reserved names.
	 */
	return apply_filters( 'subdirectory_reserved_names', $names );
}

/**
 * Send a confirmation request email when a change of network admin email address is attempted.
 *
 * The new network admin address will not become active until confirmed.
 *
 * @since 4.9.0
 *
 * @param string $old_value The old network admin email address.
 * @param string $value     The proposed new network admin email address.
 */
function update_network_option_new_admin_email( $old_value, $value ) {
	if ( get_site_option( 'admin_email' ) === $value || ! is_email( $value ) ) {
		return;
	}

	$hash            = md5( $value . time() . mt_rand() );
	$new_admin_email = array(
		'hash'     => $hash,
		'newemail' => $value,
	);
	update_site_option( 'network_admin_hash', $new_admin_email );

	$switched_locale = switch_to_locale( get_user_locale() );

	/* translators: Do not translate USERNAME, ADMIN_URL, EMAIL, SITENAME, SITEURL: those are placeholders. */
	$email_text = __(
		'Howdy ###USERNAME###,

You recently requested to have the network admin email address on
your network changed.

If this is correct, please click on the following link to change it:
###ADMIN_URL###

You can safely ignore and delete this email if you do not want to
take this action.

This email has been sent to ###EMAIL###

Regards,
All at ###SITENAME###
###SITEURL###'
	);

	/**
	 * Filters the text of the email sent when a change of network admin email address is attempted.
	 *
	 * The following strings have a special meaning and will get replaced dynamically:
	 * ###USERNAME###  The current user's username.
	 * ###ADMIN_URL### The link to click on to confirm the email change.
	 * ###EMAIL###     The proposed new network admin email address.
	 * ###SITENAME###  The name of the network.
	 * ###SITEURL###   The URL to the network.