/usr/share/acl2-7.2dfsg/books/acl2s/cgen/ is in acl2-books-source 7.2dfsg-3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/acl2s-parameter.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/basis.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/build-enumcalls.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/callback.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/cert.acl2
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/cgen-search.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/prove-cgen.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/random.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/simple-graph-array.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/top.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/type.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/utilities.lisp
/usr/share/acl2-7.2dfsg/books/acl2s/cgen/with-timeout.lisp