What give you this confidence? I discovered the list when I was trying to figure out why "link:" was no longer working, after existing for more than a decade. In another comment here, TeMPOraL says that "define:" (which is on the list) doesn't seem to be supported any more. If it's not making money for Google, and it's not necessary for their internal activities, I wouldn't want to depend on any of these to work in the future.