/usr/share/acl2-7.2dfsg/books/kestrel/ is in acl2-books-source 7.2dfsg-3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-7.2dfsg/books/kestrel/general/
/usr/share/acl2-7.2dfsg/books/kestrel/general/ensure-tests.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/general/ensure.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/general/testing-tests.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/general/testing.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/general/top.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/system/
/usr/share/acl2-7.2dfsg/books/kestrel/system/defun-sk-queries-tests.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/system/defun-sk-queries.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/system/top.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/system/world-queries-tests.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/system/world-queries.lisp
/usr/share/acl2-7.2dfsg/books/kestrel/top.lisp