/usr/share/common-lisp/source/slime/contrib/ is in cl-swank 2:2.15-1.
This file is owned by root:root, with mode 0o755.
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/usr/share/common-lisp/source/slime/contrib/swank-arglists.lisp
/usr/share/common-lisp/source/slime/contrib/swank-asdf.lisp
/usr/share/common-lisp/source/slime/contrib/swank-c-p-c.lisp
/usr/share/common-lisp/source/slime/contrib/swank-clipboard.lisp
/usr/share/common-lisp/source/slime/contrib/swank-fancy-inspector.lisp
/usr/share/common-lisp/source/slime/contrib/swank-fuzzy.lisp
/usr/share/common-lisp/source/slime/contrib/swank-hyperdoc.lisp
/usr/share/common-lisp/source/slime/contrib/swank-indentation.lisp
/usr/share/common-lisp/source/slime/contrib/swank-listener-hooks.lisp
/usr/share/common-lisp/source/slime/contrib/swank-media.lisp
/usr/share/common-lisp/source/slime/contrib/swank-motd.lisp
/usr/share/common-lisp/source/slime/contrib/swank-mrepl.lisp
/usr/share/common-lisp/source/slime/contrib/swank-package-fu.lisp
/usr/share/common-lisp/source/slime/contrib/swank-presentation-streams.lisp
/usr/share/common-lisp/source/slime/contrib/swank-presentations.lisp
/usr/share/common-lisp/source/slime/contrib/swank-repl.lisp
/usr/share/common-lisp/source/slime/contrib/swank-sbcl-exts.lisp
/usr/share/common-lisp/source/slime/contrib/swank-snapshot.lisp
/usr/share/common-lisp/source/slime/contrib/swank-sprof.lisp
/usr/share/common-lisp/source/slime/contrib/swank-trace-dialog.lisp
/usr/share/common-lisp/source/slime/contrib/swank-util.lisp