Rocket.Chat/app/oembed/client/oembedFrameWidget.html

<template name="oembedFrameWidget">
{{#if parsedUrl}}
	<blockquote class="message-oembed background-transparent-darker-before">
		{{#if meta.oembedProviderName}}
			{{#if meta.oembedProviderUrl}}
				<a href="{{meta.oembedProviderUrl}}" rel="noopener noreferrer" target="_blank" style="color: #9e9ea6">{{meta.oembedProviderName}}</a>
			{{/if}}
		{{/if}}
		{{#if meta.oembedAuthorName}}
			{{#if meta.oembedAuthorUrl}}
				<br class="only-after-a"/>
				<a href="{{meta.oembedAuthorUrl}}" rel="noopener noreferrer" target="_blank">{{meta.oembedAuthorName}}</a>
			{{/if}}
		{{/if}}
		{{#if meta.oembedTitle}}
			{{#if meta.oembedUrl}}
				<br class="only-after-a"/>
				<a href="{{meta.oembedUrl}}" rel="noopener noreferrer" target="_blank">{{meta.oembedTitle}}</a>
			{{/if}}
		{{/if}}
		{{> collapseArrow collapsedMedia=collapsedMediaVar}} <br>
		{{#unless collapsed}}
			{{#if meta.oembedDescription}}
				<p>{{meta.oembedDescription}}</p>
			{{/if}}
			{{{meta.oembedHtml}}}
		{{/unless}}
	</blockquote>
{{/if}}
</template>