The commentary section for project.el still begins with
--8<---------------cut here---------------start------------->8---
;; NOTE: The project API is still experimental and can change in major,
;; backward-incompatible ways. Everyone is encouraged to try it, and
;; report to us any problems or use cases we hadn't anticipated, by
;; sending an email to emacs-devel, or `M-x report-emacs-bug'.
--8<---------------cut here---------------end--------------->8---
Is this still true, or would it be warranted to remove it just like we
did for Xref a few years ago (9a15694a45), perhaps even in time for
Emacs 29?