/usr/share/common-lisp/source/slime/ is in cl-swank 2:2.10.1-3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/common-lisp/source/slime/contrib/
/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
/usr/share/common-lisp/source/slime/metering.lisp
/usr/share/common-lisp/source/slime/nregex.lisp
/usr/share/common-lisp/source/slime/sbcl-pprint-patch.lisp
/usr/share/common-lisp/source/slime/start-swank.lisp
/usr/share/common-lisp/source/slime/swank/
/usr/share/common-lisp/source/slime/swank-loader.lisp
/usr/share/common-lisp/source/slime/swank.asd
/usr/share/common-lisp/source/slime/swank.lisp
/usr/share/common-lisp/source/slime/swank/abcl.lisp
/usr/share/common-lisp/source/slime/swank/allegro.lisp
/usr/share/common-lisp/source/slime/swank/backend.lisp
/usr/share/common-lisp/source/slime/swank/ccl.lisp
/usr/share/common-lisp/source/slime/swank/clisp.lisp
/usr/share/common-lisp/source/slime/swank/cmucl.lisp
/usr/share/common-lisp/source/slime/swank/corman.lisp
/usr/share/common-lisp/source/slime/swank/ecl.lisp
/usr/share/common-lisp/source/slime/swank/gray.lisp
/usr/share/common-lisp/source/slime/swank/lispworks.lisp
/usr/share/common-lisp/source/slime/swank/match.lisp
/usr/share/common-lisp/source/slime/swank/mkcl.lisp
/usr/share/common-lisp/source/slime/swank/rpc.lisp
/usr/share/common-lisp/source/slime/swank/sbcl.lisp
/usr/share/common-lisp/source/slime/swank/scl.lisp
/usr/share/common-lisp/source/slime/swank/source-file-cache.lisp
/usr/share/common-lisp/source/slime/swank/source-path-parser.lisp