/lib/systemd/system/user@.service.d/timeout.conf is in systemd 237-3ubuntu10.13.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | # Avoid long hangs during shutdown if user services fail/hang due to X.org
# going away too early
[Service]
TimeoutStopSec=5
|