I actually wrote that line. IIRC the Certbot package in Devuan Jessie uses
systemd in the cron job that it ships with (the exact line is:"test -x
/usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep
int(rand(3600))' && certbot -q renew" IIRC) although I forget why (and how)
I wrote that command.