Help with IDing a table extension

Hi all.

I am trying to figure out for a family member how the extensions on this table work. To my eye, it looks like the wood for the extension probably has steel T-bar attached to it permanently, which slides into the custom cut wood sleeve that is attached to the underside of the tabletop. Am I wrong with that and is there a specific set of hardware involved?
Or, does anyone know if there exists a bit of hardware that accomplishes the same thing? Thanks everyone!

More pictures available at the website that I took these from: https://www.arhaus.com/furniture/dining-room-furniture/dining-room-tables/tuscany-extension-dining-table/

-- Bailey F - Eastern Mass.