/usr/share/acl2-6.3/books/std/ is in acl2-books 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/std/alists/
/usr/share/acl2-6.3/books/std/alists/alist-defuns.o
/usr/share/acl2-6.3/books/std/alists/alist-equiv.o
/usr/share/acl2-6.3/books/std/alists/alist-keys.o
/usr/share/acl2-6.3/books/std/alists/alist-vals.o
/usr/share/acl2-6.3/books/std/alists/alistp.o
/usr/share/acl2-6.3/books/std/alists/alists-compatible.o
/usr/share/acl2-6.3/books/std/alists/fal-extract-vals.o
/usr/share/acl2-6.3/books/std/alists/fal-extract.o
/usr/share/acl2-6.3/books/std/alists/hons-assoc-equal.o
/usr/share/acl2-6.3/books/std/alists/hons-rassoc-equal.o
/usr/share/acl2-6.3/books/std/alists/pairlis.o
/usr/share/acl2-6.3/books/std/alists/strip-cars.o
/usr/share/acl2-6.3/books/std/alists/strip-cdrs.o
/usr/share/acl2-6.3/books/std/alists/top.o
/usr/share/acl2-6.3/books/std/io/
/usr/share/acl2-6.3/books/std/io/base.o
/usr/share/acl2-6.3/books/std/io/combine.o
/usr/share/acl2-6.3/books/std/io/file-measure.o
/usr/share/acl2-6.3/books/std/io/nthcdr-bytes.o
/usr/share/acl2-6.3/books/std/io/read-file-bytes.o
/usr/share/acl2-6.3/books/std/io/read-file-characters-no-error.o
/usr/share/acl2-6.3/books/std/io/read-file-characters.o
/usr/share/acl2-6.3/books/std/io/read-file-lines.o
/usr/share/acl2-6.3/books/std/io/read-file-objects.o
/usr/share/acl2-6.3/books/std/io/read-ints.o
/usr/share/acl2-6.3/books/std/io/read-object.o
/usr/share/acl2-6.3/books/std/io/signed-byte-listp.o
/usr/share/acl2-6.3/books/std/io/take-bytes.o
/usr/share/acl2-6.3/books/std/io/top.o
/usr/share/acl2-6.3/books/std/io/unsigned-byte-listp.o
/usr/share/acl2-6.3/books/std/lists/
/usr/share/acl2-6.3/books/std/lists/acl2-count.o
/usr/share/acl2-6.3/books/std/lists/append.o
/usr/share/acl2-6.3/books/std/lists/butlast.o
/usr/share/acl2-6.3/books/std/lists/coerce.o
/usr/share/acl2-6.3/books/std/lists/duplicity.o
/usr/share/acl2-6.3/books/std/lists/equiv.o
/usr/share/acl2-6.3/books/std/lists/final-cdr.o
/usr/share/acl2-6.3/books/std/lists/flatten.o
/usr/share/acl2-6.3/books/std/lists/index-of.o
/usr/share/acl2-6.3/books/std/lists/intersection.o
/usr/share/acl2-6.3/books/std/lists/last.o
/usr/share/acl2-6.3/books/std/lists/len.o
/usr/share/acl2-6.3/books/std/lists/list-defuns.o
/usr/share/acl2-6.3/books/std/lists/list-fix.o
/usr/share/acl2-6.3/books/std/lists/make-character-list.o
/usr/share/acl2-6.3/books/std/lists/mfc-utils.o
/usr/share/acl2-6.3/books/std/lists/no-duplicatesp.o
/usr/share/acl2-6.3/books/std/lists/nth.o
/usr/share/acl2-6.3/books/std/lists/nthcdr.o
/usr/share/acl2-6.3/books/std/lists/prefixp.o
/usr/share/acl2-6.3/books/std/lists/rcons.o
/usr/share/acl2-6.3/books/std/lists/remove.o
/usr/share/acl2-6.3/books/std/lists/repeat.o
/usr/share/acl2-6.3/books/std/lists/resize-list.o
/usr/share/acl2-6.3/books/std/lists/rev.o
/usr/share/acl2-6.3/books/std/lists/revappend.o
/usr/share/acl2-6.3/books/std/lists/reverse.o
/usr/share/acl2-6.3/books/std/lists/same-lengthp.o
/usr/share/acl2-6.3/books/std/lists/sets.o
/usr/share/acl2-6.3/books/std/lists/sublistp.o
/usr/share/acl2-6.3/books/std/lists/subseq.o
/usr/share/acl2-6.3/books/std/lists/take.o
/usr/share/acl2-6.3/books/std/lists/top.o
/usr/share/acl2-6.3/books/std/lists/true-listp.o
/usr/share/acl2-6.3/books/std/misc/
/usr/share/acl2-6.3/books/std/misc/explode-atom.o
/usr/share/acl2-6.3/books/std/misc/explode-nonnegative-integer.o
/usr/share/acl2-6.3/books/std/misc/intern-in-package-of-symbol.o
/usr/share/acl2-6.3/books/std/misc/top.o
/usr/share/acl2-6.3/books/std/misc/two-nats-measure.o
/usr/share/acl2-6.3/books/std/osets/
/usr/share/acl2-6.3/books/std/osets/cardinality.o
/usr/share/acl2-6.3/books/std/osets/computed-hints.o
/usr/share/acl2-6.3/books/std/osets/delete.o
/usr/share/acl2-6.3/books/std/osets/difference.o
/usr/share/acl2-6.3/books/std/osets/instance.o
/usr/share/acl2-6.3/books/std/osets/intersect.o
/usr/share/acl2-6.3/books/std/osets/map-tests.o
/usr/share/acl2-6.3/books/std/osets/map.o
/usr/share/acl2-6.3/books/std/osets/membership.o
/usr/share/acl2-6.3/books/std/osets/outer.o
/usr/share/acl2-6.3/books/std/osets/portcullis.o
/usr/share/acl2-6.3/books/std/osets/primitives.o
/usr/share/acl2-6.3/books/std/osets/quantify.o
/usr/share/acl2-6.3/books/std/osets/sort.o
/usr/share/acl2-6.3/books/std/osets/top.o
/usr/share/acl2-6.3/books/std/osets/under-set-equiv.o
/usr/share/acl2-6.3/books/std/osets/union.o
/usr/share/acl2-6.3/books/std/strings/
/usr/share/acl2-6.3/books/std/strings/top.o
/usr/share/acl2-6.3/books/std/system/
/usr/share/acl2-6.3/books/std/system/top.o
/usr/share/acl2-6.3/books/std/top.o
/usr/share/acl2-6.3/books/std/typed-lists/
/usr/share/acl2-6.3/books/std/typed-lists/atom-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/character-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/nat-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/portcullis.o
/usr/share/acl2-6.3/books/std/typed-lists/signed-byte-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/string-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/symbol-listp.o
/usr/share/acl2-6.3/books/std/typed-lists/top.o
/usr/share/acl2-6.3/books/std/typed-lists/unsigned-byte-listp.o