Google Scholar has a useful new feature. If an article was funded from the public purse, and yet not freely published online with the agreed time, then Scholar will flag that the expected public open access version is missing.

However the flags appear on the Scholar Profile section, not as a red flag alongside each search result.

Taking a purely random example, this is what appears on the sidebar of the author’s page…

On clicking through from this widget, one gets a list with the missing papers sorted to the top…

You can see that the OA mandates are usefully itemised per-paper.