/usr/share/acl2-4.3/books/xdoc/ is in acl2-books-source 4.3-3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/acl2-4.3/books/xdoc/all.acl2
/usr/share/acl2-4.3/books/xdoc/all.lisp
/usr/share/acl2-4.3/books/xdoc/base.lisp
/usr/share/acl2-4.3/books/xdoc/cert.acl2
/usr/share/acl2-4.3/books/xdoc/defxdoc-raw.acl2
/usr/share/acl2-4.3/books/xdoc/defxdoc-raw.lisp
/usr/share/acl2-4.3/books/xdoc/display.lisp
/usr/share/acl2-4.3/books/xdoc/import-acl2doc.lisp
/usr/share/acl2-4.3/books/xdoc/make-manual.acl2
/usr/share/acl2-4.3/books/xdoc/make-manual.lisp
/usr/share/acl2-4.3/books/xdoc/mkdir-raw.acl2
/usr/share/acl2-4.3/books/xdoc/mkdir-raw.lisp
/usr/share/acl2-4.3/books/xdoc/mkdir.lisp
/usr/share/acl2-4.3/books/xdoc/names.lisp
/usr/share/acl2-4.3/books/xdoc/parse-xml.lisp
/usr/share/acl2-4.3/books/xdoc/portcullis.acl2
/usr/share/acl2-4.3/books/xdoc/portcullis.lisp
/usr/share/acl2-4.3/books/xdoc/preprocess.lisp
/usr/share/acl2-4.3/books/xdoc/save.lisp
/usr/share/acl2-4.3/books/xdoc/top.lisp
/usr/share/acl2-4.3/books/xdoc/topics.lisp
/usr/share/acl2-4.3/books/xdoc/write-acl2-xdoc.lisp