/usr/share/emacs/site-lisp/acl2/ is in acl2-emacs 8.0dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/emacs/site-lisp/acl2/acl2-doc.el
/usr/share/emacs/site-lisp/acl2/acl2-interface-functions.el
/usr/share/emacs/site-lisp/acl2/acl2-interface.el
/usr/share/emacs/site-lisp/acl2/acl2-mode.el
/usr/share/emacs/site-lisp/acl2/emacs-acl2.el
/usr/share/emacs/site-lisp/acl2/inf-acl2.el
/usr/share/emacs/site-lisp/acl2/interface-macros.el
/usr/share/emacs/site-lisp/acl2/key-interface.el
/usr/share/emacs/site-lisp/acl2/load-inferior-acl2.el
/usr/share/emacs/site-lisp/acl2/load-shell-acl2.el
/usr/share/emacs/site-lisp/acl2/mfm-acl2.el
/usr/share/emacs/site-lisp/acl2/mfm.el
/usr/share/emacs/site-lisp/acl2/monitor.el
/usr/share/emacs/site-lisp/acl2/top-start-inferior-acl2.el
/usr/share/emacs/site-lisp/acl2/top-start-shell-acl2.el