Rocket.Chat/packages/rocketchat-oembed/client/oembedVideoWidget.html

<template name="oembedVideoWidget">
{{#if parsedUrl}}
	<blockquote>
		<div><a href="{{url}}">{{parsedUrl.host}}</a></div>
		<div>{{title}}</div>
		<video controls class="inline-video">
			<source src="{{url}}" type="{{contentType}}">
			Your browser does not support the video element.
		</video>
	</blockquote>
{{/if}}
</template>