Mail app V 16- "On My Mac" folders for local storage

Have the "On My Mac" folders been discontinued in V16 of Mac Mail? I recently went looking for them for a project to store/archive some old emails, and in the past I could simply create new folders and sub-folders in On My Mac and just drag old mail to the, but I don't actually see On My Mac folders at all on either of my machine with Ventura.