I like to think of it as an open-standard like where anyone can download the TCK versus something where you need to pay for the SPECs from ISO (for example Prol

I like to think of it as an open-standard like where anyone can download the TCK versus something where you need to pay for the SPECs from ISO (for example Prolog is https://www.iso.org/standard/21413.html https://www.iso.org/standard/21413.html which is 185€/$250 USD).