/usr/share/acl2-7.1/books/textbook/chap11/ is in acl2-books 7.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-7.1/books/textbook/chap11/compress.o
/usr/share/acl2-7.1/books/textbook/chap11/encap.o
/usr/share/acl2-7.1/books/textbook/chap11/finite-sets.o
/usr/share/acl2-7.1/books/textbook/chap11/how-many-soln1.o
/usr/share/acl2-7.1/books/textbook/chap11/how-many-soln2.o
/usr/share/acl2-7.1/books/textbook/chap11/mergesort.o
/usr/share/acl2-7.1/books/textbook/chap11/perm-append.o
/usr/share/acl2-7.1/books/textbook/chap11/perm.o
/usr/share/acl2-7.1/books/textbook/chap11/qsort.o
/usr/share/acl2-7.1/books/textbook/chap11/starters.o
/usr/share/acl2-7.1/books/textbook/chap11/summations-book.o
/usr/share/acl2-7.1/books/textbook/chap11/summations.o
/usr/share/acl2-7.1/books/textbook/chap11/tautology.o
/usr/share/acl2-7.1/books/textbook/chap11/xtr.o
/usr/share/acl2-7.1/books/textbook/chap11/xtr2.o