/usr/share/acl2-8.0dfsg/books/kestrel/abnf/ is in acl2-books-source 8.0dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/abstract-syntax.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/abstractor.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/cert.acl2
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/concrete-syntax.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/core-rules.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/examples.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/operations.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/parser-and-abstractor-validation.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/parser.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/portcullis.acl2
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/portcullis.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/semantics.lisp
/usr/share/acl2-8.0dfsg/books/kestrel/abnf/top.lisp