Ghost/ghost/admin/app/components/modal-leave-editor.hbs

<header class="modal-header">
    <h1>Are you sure you want to leave this page?</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>
        Hey there! It looks like you're in the middle of writing something and
        you haven't saved all of your content.
    </p>

    <p>Save before you go!</p>
</div>

<div class="modal-footer">
    <button {{action "closeModal"}} class="gh-btn"><span>Stay</span></button>
    <button {{action "confirm"}} class="gh-btn gh-btn-red"><span>Leave</span></button>
</div>