Google has discontinued its support for video carousel markup and has thus removed it from its video structured data help documentation. Initially, Google tested video carousel on a limited number of sites and is now saying that it "ultimately found that it wasn't useful for the ecosystem at scale."
Google wrote they have "Removed video carousel guidance from the video structured data documentation." Adding, "We initially tested video carousel markup with a group of site owners, and ultimately found that it wasn't useful for the ecosystem at scale."
Google said you can "leave the markup on your site so that search engines and other systems can better understand your web page."
What were video carousels? Google wrote in the archived documentation:
Video host carousel (limited access): Enable users to explore your video gallery pages by adding ItemList structured data. This feature is currently limited to a small set of providers. Google Search may automatically show a host carousel for your site without you having to add ItemList structured data.
Google also removed other references in the documentation to video carousels.
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