/usr/share/acl2-6.3/books/system/pcert/ is in acl2-books-certs 6.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-1.cert/
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-1.cert/acl2x-pcert-test-1.pcert0
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-2-include.cert/
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-2-include.cert/acl2x-pcert-test-2-include.pcert0
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-2.cert/
/usr/share/acl2-6.3/books/system/pcert/acl2x-pcert-test-2.cert/acl2x-pcert-test-2.pcert0
/usr/share/acl2-6.3/books/system/pcert/elide-test.cert/
/usr/share/acl2-6.3/books/system/pcert/elide-test.cert/elide-test.pcert0
/usr/share/acl2-6.3/books/system/pcert/mid.cert/
/usr/share/acl2-6.3/books/system/pcert/mid.cert/mid.pcert0
/usr/share/acl2-6.3/books/system/pcert/pkg-test.cert/
/usr/share/acl2-6.3/books/system/pcert/pkg-test.cert/pkg-test.pcert0
/usr/share/acl2-6.3/books/system/pcert/sub.cert/
/usr/share/acl2-6.3/books/system/pcert/sub.cert/sub.pcert0
/usr/share/acl2-6.3/books/system/pcert/top.cert/
/usr/share/acl2-6.3/books/system/pcert/top.cert/top.pcert0