/usr/lib/X11/ is in x11-apps 7.7+6ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/X11/x11perfcomp/
/usr/lib/X11/x11perfcomp/Xmark
/usr/lib/X11/x11perfcomp/fillblnk
/usr/lib/X11/x11perfcomp/perfboth
/usr/lib/X11/x11perfcomp/perfratio
/usr/lib/X11/xedit/
/usr/lib/X11/xedit/lisp/
/usr/lib/X11/xedit/lisp/indent.lsp
/usr/lib/X11/xedit/lisp/lisp.lsp
/usr/lib/X11/xedit/lisp/progmodes/
/usr/lib/X11/xedit/lisp/progmodes/auto.lsp
/usr/lib/X11/xedit/lisp/progmodes/c.lsp
/usr/lib/X11/xedit/lisp/progmodes/html.lsp
/usr/lib/X11/xedit/lisp/progmodes/imake.lsp
/usr/lib/X11/xedit/lisp/progmodes/lisp.lsp
/usr/lib/X11/xedit/lisp/progmodes/make.lsp
/usr/lib/X11/xedit/lisp/progmodes/man.lsp
/usr/lib/X11/xedit/lisp/progmodes/patch.lsp
/usr/lib/X11/xedit/lisp/progmodes/perl.lsp
/usr/lib/X11/xedit/lisp/progmodes/python.lsp
/usr/lib/X11/xedit/lisp/progmodes/rpm.lsp
/usr/lib/X11/xedit/lisp/progmodes/sgml.lsp
/usr/lib/X11/xedit/lisp/progmodes/sh.lsp
/usr/lib/X11/xedit/lisp/progmodes/xconf.lsp
/usr/lib/X11/xedit/lisp/progmodes/xlog.lsp
/usr/lib/X11/xedit/lisp/progmodes/xrdb.lsp
/usr/lib/X11/xedit/lisp/syntax.lsp
/usr/lib/X11/xedit/lisp/xedit.lsp