racket/racket/collects/realm

If you're reading _Realm of Racket_ and looking for programs in

  ../../collects/realm

then you should be able to find them in

  ../../pkgs/realm

or

 ../../share/pkgs/realm

instead.

The files moved as part of a reorganization of Racket into packages.
Although the "realm" collection is still included in the main Racket
distribution, it's now the "realm" package.