Ghost-Admin/app/components/modal-delete-all.hbs

<header class="modal-header">
    <h1>Would you really like to delete all content from your blog?</h1>
</header>
<a class="close" href="" role="button" title="Close" {{action "closeModal"}}>{{svg-jar "close"}}<span class="hidden">Close</span></a>

<div class="modal-body">
    <p>This is permanent! No backups, no restores, no magic undo button. We warned you, k?</p>
</div>

<div class="modal-footer">
    <button {{action "closeModal"}} class="gh-btn"><span>Cancel</span></button>
    <GhTaskButton @buttonText="Delete" @successText="Deleted" @task={{this.deleteAll}} @class="gh-btn gh-btn-red gh-btn-icon" />
</div>