Following the Wiki here one could establish a cron job for the user "acme", which I did using:
acme@mail:~/.acme.sh$ acme.sh --install-cronjob
[Tue Nov 14 02:33:50 PM CET 2023] Using the current script from: /usr/local/share/acme.sh/acme.sh
[Tue Nov 14 02:33:50 PM CET 2023] Installing cron job
no crontab for acme
no crontab for acme
OK, minute 50, hour 21, was obvious, and not my question . From where does acme.sh know to renew after 60days. That was my question. Is it hardwired into acme.sh somewhere?
It's coded in as a default, but can be changed with some command-line option if you want. But 60 days is a pretty sensible default for Let's Encrypt's 90-day certs.
Yes, I know what it does. Why? Why would you want to wait that long? Sure, you can. But you're overriding both the client's default and the explicit recommendation of the CA. To what end?