zulip/static/templates/settings/deactivation_stream_modal.hbs

<div id="deactivation_stream_modal" class="modal modal-bg hide fade new-style" tabindex="-1" role="dialog" aria-labelledby="deactivation_stream_modal_label" aria-hidden="true">
    <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="{{t 'Close' }}"><span aria-hidden="true">&times;</span></button>
        <h3 id="deactivation_stream_modal_label">{{t "Delete stream" }} <span class="stream_name">{{stream_name}}</span></h3>
    </div>
    <div class="modal-body">
        <p>{{t "Deleting this stream will immediately unsubscribe everyone, and the stream's content will not be recoverable." }} <strong>{{t "Are you sure you want to do this?" }}</strong></p>
    </div>
    <div class="modal-footer">
        <button class="button rounded" data-dismiss="modal">{{t "Cancel" }}</button>
        <button class="button rounded btn-danger" id="do_deactivate_stream_button" data-stream-id="{{stream_id}}">{{t "Yes, delete this stream" }}</button>
    </div>
</div>