/usr/share/common-lisp/source/ is in cl-unicode 0.1.5-3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/common-lisp/source/cl-unicode/
/usr/share/common-lisp/source/cl-unicode/alias.lisp
/usr/share/common-lisp/source/cl-unicode/api.lisp
/usr/share/common-lisp/source/cl-unicode/cl-unicode.asd
/usr/share/common-lisp/source/cl-unicode/conditions.lisp
/usr/share/common-lisp/source/cl-unicode/derived.lisp
/usr/share/common-lisp/source/cl-unicode/hash-tables.lisp
/usr/share/common-lisp/source/cl-unicode/lists.lisp
/usr/share/common-lisp/source/cl-unicode/methods.lisp
/usr/share/common-lisp/source/cl-unicode/packages.lisp
/usr/share/common-lisp/source/cl-unicode/specials.lisp
/usr/share/common-lisp/source/cl-unicode/test-functions.lisp
/usr/share/common-lisp/source/cl-unicode/util.lisp