/usr/share/acl2-6.3/books/centaur/esim/ is in acl2-books 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/centaur/esim/esim-cut.o
/usr/share/acl2-6.3/books/centaur/esim/esim-paths.o
/usr/share/acl2-6.3/books/centaur/esim/esim-primitives.o
/usr/share/acl2-6.3/books/centaur/esim/esim-sexpr-correct.o
/usr/share/acl2-6.3/books/centaur/esim/esim-sexpr-support-thms.o
/usr/share/acl2-6.3/books/centaur/esim/esim-sexpr-support.o
/usr/share/acl2-6.3/books/centaur/esim/esim-sexpr.o
/usr/share/acl2-6.3/books/centaur/esim/esim-spec.o
/usr/share/acl2-6.3/books/centaur/esim/esim-vcd.o
/usr/share/acl2-6.3/books/centaur/esim/esim-vl.o
/usr/share/acl2-6.3/books/centaur/esim/follow-backwards.o
/usr/share/acl2-6.3/books/centaur/esim/local-theory.o
/usr/share/acl2-6.3/books/centaur/esim/plist.o
/usr/share/acl2-6.3/books/centaur/esim/portcullis.o
/usr/share/acl2-6.3/books/centaur/esim/steps.o
/usr/share/acl2-6.3/books/centaur/esim/stv/
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-compile.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-debug.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-doc.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-expand.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-run.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-sim.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-top.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-util.o
/usr/share/acl2-6.3/books/centaur/esim/stv/stv-widen.o