/etc/default/devpts is in initscripts 2.88dsf-59.3ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | # GID of the `tty' group
TTYGRP=5
# Set to 600 to have `mesg n' be the default
TTYMODE=620
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