zulip/static/templates/change_stream_info_modal.hbs

<div id="change_stream_info_modal" class="modal modal-bg hide fade new-style" tabindex="-1"
  role="dialog" aria-labelledby="change_stream_info_label" aria-hidden="true">
    <div class="modal-header">
        <button type="button" class="close close-change-stream-info-modal" data-dismiss="modal" aria-label="{{t 'Close' }}">
            <span aria-hidden="true">&times;</span>
        </button>
        <h3 id="change_stream_info_label">
            {{#tr}}Edit #{stream_name}{{/tr}}
            <span class="email"></span>
        </h3>
    </div>
    <div class="modal-body">
        <div class="input-group">
            <label for="change_stream_name">
                {{t 'Stream name' }}
            </label>
            <input type="text" id="change_stream_name" value="{{ stream_name }}" />
        </div>
        <div class="input-group">
            <label for="change_stream_description">
                {{t 'Description' }}
            </label>
            <textarea id="change_stream_description" maxlength="1000">{{ stream_description }}</textarea>
        </div>
    </div>

    <div class="modal-footer">
        <button class=" button rounded close-change-stream-info-modal" data-dismiss="modal">{{t "Cancel" }}</button>
        <button class="button rounded btn-danger save-button" id="save_stream_info"
          tabindex="-1" data-stream-id="{{stream_id}}">
            {{t "Save changes"}}
        </button>
    </div>
</div>