public/scripts/templates/deleteConfirm.html

<b><span data-i18n="THIS IS PERMANENT!">THIS IS PERMANENT!</span><br><br>
<label for="del_char_checkbox" class="checkbox_label justifyCenter">
    <input type="checkbox" id="del_char_checkbox" />
    <small data-i18n="Also delete the chat files">Also delete the chat files</small>
</label></b>