Example: the before / after comparator, images and videos
This page shows the site's before / after comparator, with images and video. It is not listed: neither in the guides index nor in search engines.
Two images
Drag the green handle, or click anywhere in the image.
SOURCE

DLSS 5

Two videos
The two videos play together under the cursor. The button at the top right pauses them.
SOURCE
DLSS 5
A single video in the text
In the editor, the “Image in text” and “Before / after comparator” buttons accept images and MP4 or WebM videos.