/usr/share/acl2-7.1/books/arithmetic-5/lib/ is in acl2-books-source 7.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/arithmetic-theory.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/banner.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/basic.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/building-blocks-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/building-blocks.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/collect.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/common.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/default-hint.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/distributivity.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/dynamic-e-d.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/elim-hint.acl2
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/elim-hint.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/expt-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/expt.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/forcing-types.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/if-normalization.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/integerp-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/integerp-meta.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/integerp.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/mini-theories.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/natp-posp.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/normalize.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/numerator-and-denominator.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/remove-weak-inequalities.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/simple-equalities-and-inequalities-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/simple-equalities-and-inequalities.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/simplify-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/simplify.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/top.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/types-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/types.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/basic-ops/we-are-here.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/floor-mod-basic-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/floor-mod-basic.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/floor-mod-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/floor-mod.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/forcing-types.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/if-normalization.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/logand-helper.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/logand.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/mod-expt-fast.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/more-floor-mod.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/top.lisp
/usr/share/acl2-7.1/books/arithmetic-5/lib/floor-mod/truncate-rem.lisp