Ghost/ghost/admin/app/components/modals/editor/confirm-leave.hbs

<div class="modal-content" data-test-modal="unsaved-post-changes">
    <header class="modal-header">
        <h1>Are you sure you want to leave this page?</h1>
    </header>
    <button class="close" title="Close" type="button" {{on "click" @close}}>{{svg-jar "close"}}<span class="hidden">Close</span></button>

    <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 class="gh-btn" data-test-stay-button type="button" {{on "click" @close}}><span>Stay</span></button>
        <button class="gh-btn gh-btn-red" data-test-leave-button type="button" {{on "click" (fn @close true)}}><span>Leave</span></button>
    </div>

</div>