Spotlight provides out-of-the-box accessibility support for exhibits when possible, but exhibit curators are ultimately responsible for ensuring their content is accessible.
Images
uploaded images: caption
embedded exhibit items: title
Videos
transcripts, captions
Iframes
if using ids in iframe code, use unique ids
https://learn.canvas.cornell.edu/getting-started-with-kaltura/
Use the title attribute to describe the iframe's content: https://www.w3.org/WAI/WCAG21/Techniques/html/H64
<iframe src="LINK" title="Kaltura video: TITLE OF VIDEO">