mtb_dcatadmin_plus/resources/views/distributor/form/button.blade.php

<div class="{{$viewClass['form-group']}}">

    <label class="{{$viewClass['label']}} control-label"></label>

    <div class="{{$viewClass['field']}}">
        <span class="btn {{ $class }} {{ $buttonClass }}" {!! $attributes !!}>{!! $label !!}</span>
    </div>
</div>