John Mueller of Google was asked if the Google Search Console coverage report can show the unavailable_after meta tag in that report. John said he doubts it because it is "too niche."
This was a question that came up on Twitter, here are those tweets:
Hi @JohnMu, Why is the unavailable_after meta tag not showing up in coverage reports? Any plans for it to appear?
— Samet Özsüleyman (@sametozsuleyman) April 16, 2021
I doubt it - too niche. Sorry!
— 🐄 John 🐄 (@JohnMu) December 29, 2021
Google first supported the unavailable after meta tag in 2007 and still supports it today. In fact, Google has recommended its use for out of stock products and other situations numerous times over the years.
The unavailable after meta tag will not show this page in search results after the specified date/time. The date/time must be specified in a widely adopted format including, but not limited to RFC 822, RFC 850, and ISO 8601. The directive is ignored if no valid date/time is specified. By default there is no expiration date for content.
Note, if you use it and you don't specify this directive, this page may be shown in search results indefinitely. Also Googlebot will decrease the crawl rate of the URL considerably after the specified date and time.
Forum discussion at Twitter.