/usr/share/acl2-6.3/books/arithmetic-3/ is in acl2-books-source 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/arithmetic-theory.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/banner.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/basic-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/basic.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/building-blocks.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/collect.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/common.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/default-hint.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/integerp-meta.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/integerp.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/mini-theories-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/mini-theories.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/normalize.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/numerator-and-denominator.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/remove-weak-inequalities.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/simplify-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/simplify.lisp
/usr/share/acl2-6.3/books/arithmetic-3/bind-free/top.lisp
/usr/share/acl2-6.3/books/arithmetic-3/extra/
/usr/share/acl2-6.3/books/arithmetic-3/extra/ext.lisp
/usr/share/acl2-6.3/books/arithmetic-3/extra/top-ext.lisp
/usr/share/acl2-6.3/books/arithmetic-3/floor-mod/
/usr/share/acl2-6.3/books/arithmetic-3/floor-mod/floor-mod.lisp
/usr/share/acl2-6.3/books/arithmetic-3/floor-mod/mod-expt-fast.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/
/usr/share/acl2-6.3/books/arithmetic-3/pass1/basic-arithmetic-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/basic-arithmetic.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/expt-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/expt.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/inequalities.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/mini-theories.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/non-linear.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/num-and-denom-helper.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/numerator-and-denominator.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/prefer-times.lisp
/usr/share/acl2-6.3/books/arithmetic-3/pass1/top.lisp
/usr/share/acl2-6.3/books/arithmetic-3/top.lisp