The source – developers.google.com
The company removed the SeekToAction markup from beta for automatic highlighting in video chapters. This markup applies only to videos embedded in the site.
If you tell Google a URL pattern to navigate to a specific timestamp in a video, it will then use it to identify key points in the video and display links directly to those moments in search results.
Thus, this feature allows users to jump directly to the fragment of interest. But the ability to mark key moments manually (Clip) remains. You can opt out of the highlights function using the nosnippet meta tag.
When publishing videos to third-party platforms, you need to find out if they support schema.org markup.