/usr/lib/x86_64-linux-gnu/ is in x11-session-utils 7.7+2build1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/X11/
/usr/lib/x86_64-linux-gnu/X11/rstart/
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/@List
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/ListContexts
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/ListGenericCommands
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x11r6/
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x11r6/@List
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x11r6/LoadMonitor
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x11r6/Terminal
/usr/lib/x86_64-linux-gnu/X11/rstart/config
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/@List
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/default
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/x11r6
/usr/lib/x86_64-linux-gnu/X11/rstart/rstartd.real
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x
/usr/lib/x86_64-linux-gnu/X11/rstart/commands/x11
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/x
/usr/lib/x86_64-linux-gnu/X11/rstart/contexts/x11