maintenance/application/admin/command/Crud/stubs/html/fieldlist.stub

            <dl class="fieldlist" data-name="{%fieldName%}">
                <dd>
                    <ins>{:__('{%itemKey%}')}</ins>
                    <ins>{:__('{%itemValue%}')}</ins>
                </dd>
                <dd><a href="javascript:;" class="btn btn-sm btn-success btn-append"><i class="fa fa-plus"></i> {:__('Append')}</a></dd>
                <textarea name="{%fieldName%}" class="form-control hide" cols="30" rows="5">{%fieldValue%}</textarea>
            </dl>