/usr/share/acl2-6.3/books/centaur/aig/ is in acl2-books-certs 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/centaur/aig/accumulate-nodes-vars.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-base.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-equivs.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-print.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-sat.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-vars-ext.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-vars-fast.cert
/usr/share/acl2-6.3/books/centaur/aig/aig-vars.cert
/usr/share/acl2-6.3/books/centaur/aig/aig2c.cert
/usr/share/acl2-6.3/books/centaur/aig/aiger.cert
/usr/share/acl2-6.3/books/centaur/aig/base.cert
/usr/share/acl2-6.3/books/centaur/aig/bddify-correct.cert
/usr/share/acl2-6.3/books/centaur/aig/bddify.cert
/usr/share/acl2-6.3/books/centaur/aig/best-aig.cert
/usr/share/acl2-6.3/books/centaur/aig/eval-restrict.cert
/usr/share/acl2-6.3/books/centaur/aig/faig-base.cert
/usr/share/acl2-6.3/books/centaur/aig/faig-constructors.cert
/usr/share/acl2-6.3/books/centaur/aig/faig-equivs.cert
/usr/share/acl2-6.3/books/centaur/aig/faig-purebool-p.cert
/usr/share/acl2-6.3/books/centaur/aig/g-aig-eval.cert
/usr/share/acl2-6.3/books/centaur/aig/induction.cert
/usr/share/acl2-6.3/books/centaur/aig/misc.cert
/usr/share/acl2-6.3/books/centaur/aig/portcullis.cert
/usr/share/acl2-6.3/books/centaur/aig/random-sim.cert
/usr/share/acl2-6.3/books/centaur/aig/three-four.cert
/usr/share/acl2-6.3/books/centaur/aig/top.cert
/usr/share/acl2-6.3/books/centaur/aignet/aig-cnf.cert
/usr/share/acl2-6.3/books/centaur/aignet/aig-sim.cert
/usr/share/acl2-6.3/books/centaur/aignet/aignet-absstobj.cert
/usr/share/acl2-6.3/books/centaur/aignet/aignet-exec-thms.cert
/usr/share/acl2-6.3/books/centaur/aignet/aignet-exec.cert
/usr/share/acl2-6.3/books/centaur/aignet/aignet-logic-interface.cert
/usr/share/acl2-6.3/books/centaur/aignet/aignet-logic.cert
/usr/share/acl2-6.3/books/centaur/aignet/arrays.cert
/usr/share/acl2-6.3/books/centaur/aignet/bit-lemmas.cert
/usr/share/acl2-6.3/books/centaur/aignet/cnf.cert
/usr/share/acl2-6.3/books/centaur/aignet/construction.cert
/usr/share/acl2-6.3/books/centaur/aignet/copying.cert
/usr/share/acl2-6.3/books/centaur/aignet/eval.cert
/usr/share/acl2-6.3/books/centaur/aignet/from-hons-aig.cert
/usr/share/acl2-6.3/books/centaur/aignet/litp.cert
/usr/share/acl2-6.3/books/centaur/aignet/portcullis.cert
/usr/share/acl2-6.3/books/centaur/aignet/prune.cert
/usr/share/acl2-6.3/books/centaur/aignet/refcounts.cert
/usr/share/acl2-6.3/books/centaur/aignet/semantics.cert
/usr/share/acl2-6.3/books/centaur/aignet/snodes.cert
/usr/share/acl2-6.3/books/centaur/aignet/to-hons-aig.cert
/usr/share/acl2-6.3/books/centaur/aignet/types.cert
/usr/share/acl2-6.3/books/centaur/aignet/vecsim.cert