AdSense is redesigning the Sites tab to make it more user-friendly.
Going forward, you can only add domains, subdomains whose domain is listed on the public suffix list, and sites that are managed by AdSense platform partners as "Sites" to AdSense.
You will no longer be able to add or manage subdomains that are part of an existing Site in the Sites tab, but this will not impact ad serving or your earnings.
Any existing blocking controls for a subdomain will be promoted to the domain level.
AdSense is introducing a new ads.txt column to the Sites table to show you the ads.txt status for your sites.
You will start getting faster feedback for certain types of issues we find with your sites during the initial review process.
AdSense is always looking for ways to improve its performance and usability, and your feedback is appreciated. The email provides a link for more information to help you adjust your settings.