I can confirm that currently (with Ubuntu 20.04 already published), a search for a non-existing manpage opens a google customized search that allows filtering for obsolete Ubuntu releases
All Hardy (8.04) Precise (12.04) Lucid (10.04) Natty (11.04) Oneiric (11.10)
see screenshot in the attachment.
I can confirm that currently (with Ubuntu 20.04 already published), a search for a non-existing manpage opens a google customized search that allows filtering for obsolete Ubuntu releases
All Hardy (8.04) Precise (12.04) Lucid (10.04) Natty (11.04) Oneiric (11.10)
see screenshot in the attachment.