/usr/share/acl2-7.1/books/data-structures/ is in acl2-books 7.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-7.1/books/data-structures/alist-defthms.o
/usr/share/acl2-7.1/books/data-structures/alist-defuns.o
/usr/share/acl2-7.1/books/data-structures/alist-theory.o
/usr/share/acl2-7.1/books/data-structures/array1.o
/usr/share/acl2-7.1/books/data-structures/defalist.o
/usr/share/acl2-7.1/books/data-structures/deflist.o
/usr/share/acl2-7.1/books/data-structures/list-defthms.o
/usr/share/acl2-7.1/books/data-structures/list-defuns.o
/usr/share/acl2-7.1/books/data-structures/list-theory.o
/usr/share/acl2-7.1/books/data-structures/memories/
/usr/share/acl2-7.1/books/data-structures/memories/log2.o
/usr/share/acl2-7.1/books/data-structures/memories/memory-impl.o
/usr/share/acl2-7.1/books/data-structures/memories/memory.o
/usr/share/acl2-7.1/books/data-structures/memories/memtree.o
/usr/share/acl2-7.1/books/data-structures/memories/private.o
/usr/share/acl2-7.1/books/data-structures/no-duplicates.o
/usr/share/acl2-7.1/books/data-structures/number-list-defthms.o
/usr/share/acl2-7.1/books/data-structures/number-list-defuns.o
/usr/share/acl2-7.1/books/data-structures/number-list-theory.o
/usr/share/acl2-7.1/books/data-structures/portcullis.o
/usr/share/acl2-7.1/books/data-structures/set-defthms.o
/usr/share/acl2-7.1/books/data-structures/set-defuns.o
/usr/share/acl2-7.1/books/data-structures/set-theory.o
/usr/share/acl2-7.1/books/data-structures/structures.o
/usr/share/acl2-7.1/books/data-structures/top.o
/usr/share/acl2-7.1/books/data-structures/utilities.o