all-in-one-event-calendar/public/admin/video_modal.php

<div class="ai1ec-modal ai1ec-fade timely" id="ai1ec-video-modal"
    style="width: 600px; margin-left: -300px; margin-top: -200px;">
    <div class="ai1ec-modal-dialog">
        <div class="ai1ec-modal-content">
            <div class="ai1ec-modal-header">
                <button class="ai1ec-close" data-dismiss="ai1ec-modal">×</button>
                <h1><small><?php echo esc_html( $title ); ?></small></h1>
            </div>
            <div id="ai1ec-video"></div>
            <?php if ( isset( $footer ) ): ?>
                <div class="ai1ec-modal-footer">
                    <?php echo $footer; ?>
                </div>
            <?php endif; ?>
        </div>
    </div>
</div>

<script type="text/javascript">
/* <![CDATA[ */
    // TODO: Localize this variable using requirejs-suitable technique rather than
    // this way.
    var ai1ecVideo = {
        youtubeId: '<?php echo $youtube_id; ?>'
    };
/* ]]> */
</script>