It's not uncommon for a Distro to point NetworkManager or whoever to check for connectivity using their own servers, Arch does it themselves[0].

[0] ping.archlinux.org

Note that the certbot instructions are to renew 2x a day with up to one hour of randomized delay; using @monthly as suggested here will result in occasional outages if the "once a month" renewal attempt fails in two consecutive months due to transient peak service blips (such as those caused by '@monthly' hardcoding for month X day 1 time 00:00 often UTC without randomization), especially as Let's Encrypt drops their lifetimes to 45 days over the next 2 years, which would result in certificates avoidably expiring in production. Please instead use certbot's recommended 2x/day renew with a random sleep of up to an hour before initiating each attempt; at least one of cronie, at, bash, python, perl random sleep methods are available on most* platforms, and are offered up by the crontab-command generator at https://certbot.eff.org/instructions .

* There is a stack overflow page from 2016 filled with solutions for Busybox, so I'd say 'all' rather than 'some' but someone out there is hosting a webserver on a potato, so better safe than sorry.

Certbot would be like the supply chain attack holy grail. Not sure I'd want software like that running unmonitored automatically with root privileges.