winter/modules/system/partials/_settings_menu_toolbar.php

<div class="layout control-toolbar">
    <div class="layout-cell">
        <div class="relative toolbar-item loading-indicator-container size-input-text">
            <input placeholder="<?= e(trans('system::lang.settings.search')) ?>" type="text" name="search" value="" 
                class="form-control icon search"
                id="settings-search-input"
                autocomplete="off"
                data-track-input
                data-load-indicator
                data-load-indicator-opaque
            />
        </div>
    </div>
</div>