/lib/udev/rules.d/67-azure-console.rules is in walinuxagent 2.2.21+really2.2.20-0ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # Enable verbose console logging on the serial console for Azure.
KERNEL=="console", GROUP="syslog", MODE="0620"
|