/usr/share/acl2-6.3/books/centaur/defrstobj/ is in acl2-books-source 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/centaur/defrstobj/array-lemmas.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/basic-tests.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/cert.acl2
/usr/share/acl2-6.3/books/centaur/defrstobj/def-typed-record.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/defrstobj.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/fancy-worseguy.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/g-delete-keys.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/array-rec.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/cert.acl2
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/demo1.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/demo2.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/demo3.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/demo4.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/demo5.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/groundwork/local.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/portcullis.acl2
/usr/share/acl2-6.3/books/centaur/defrstobj/portcullis.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/typed-record-tests.lisp
/usr/share/acl2-6.3/books/centaur/defrstobj/typed-records.lisp