I couldnt find any documentation on "Site rename operation extendend storage" site collection scoped feature. Can any one share the details if you happen to know.
I searched online and could not find anything about this feature. It should be a new feature in SharePoint Online. I also try to activate it, however, there is nothing changed.
Maybe you need to wait for the official documents.
Or, you can create a new service request about this issue in Admin Center->Support. More Professional will assist you with this feature.
It looks like this feature will be used to rename the site (with o365 groups in sponline we have lost ability to rename the site, you need to create a new one and migrate the content, while in SPon prem you can just run cmdlet to rename the site)
I only could find that this feature is creating a hidden list in SPO: