/etc/logrotate.d/exim4-paniclog is in exim4-base 4.76-3ubuntu3.4.
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 6 7 8 9  | /var/log/exim4/paniclog {
	size 10M
	missingok
	rotate 10
	compress
	delaycompress
	notifempty
	create 640 Debian-exim adm
}
 |