Unfortunately, it is marked obsolete since 29.1. The NEWS says:
* Many seldom-used generalized variables have been made obsolete.
Emacs has a number of rather obscure generalized variables defined,
that, for instance, allowed you to say things like:
(setf (point-min) 4)
These never caught on and have been made obsolete. The form above,
for instance, is the same as saying
* Many seldom-used generalized variables have been made obsolete. Emacs has a number of rather obscure generalized variables defined, that, for instance, allowed you to say things like:
These never caught on and have been made obsolete. The form above, for instance, is the same as saying