File: themes/backend/components/core/modal.twig

<div class="modal" id="dynamic-modal-{{ identifier }}" data-bs-backdrop="static" data-bs-keyboard="false" role="dialog" aria-labelledby="dynamic-modal-{{ identifier }}-title" aria-hidden="true">
    <div class="modal-dialog modal-dialog-centered {{ meta.modal_size }}" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="dynamic-modal-{{ identifier }}-title">
                    <i class="{{ meta.icon ?? 'mdi mdi-loading mdi-spin' }}"></i> 
                    <span class="modal-title-text">
                    {{ meta.title ?? phrase('Loading') }}
                    </span>
                </h5>
                <button type="button" class="btn-close" data-bs-dismiss="modal" data-dismiss="modal" aria-label="{{ phrase('Close') }}"></button>
            </div>
            <div class="modal-body">
                {% if content %}
                    {{ content }}
                {% else %}
                    <div class="d-flex justify-content-center">
                        <div class="spinner-border text-primary" role="status">
                            <span class="visually-hidden sr-only">
                                {{ phrase('Loading') }}
                            </span>
                        </div>
                    </div>
                {% endif %}
            </div>
        </div>
    </div>
</div>