For the documented following openntpd-service-type definition:
--8<---------------cut here---------------start------------->8---
(openntpd-configuration
(listen-on '("127.0.0.1" "::1"))
(sensor '("udcf0 correction 70000"))
(constraint-from '("www.gnu.org"))
(constraints-from '("https://www.google.com/";))
(allow-large-adjustment? #t)))
--8<---------------cut here---------------end--------------->8---
The following configuration file is generated:
--8<---------------cut here---------------start------------->8---
listen on 127.0.0.1
listen on ::1
constraints from "https://www.google.com/";
constraints from "https://www.google.com/";
sensor udcf0 correction 70000
constraints from "https://www.google.com/";
server 0.guix.pool.ntp.org
server 1.guix.pool.ntp.org
server 2.guix.pool.ntp.org
server 3.guix.pool.ntp.org
constraints from "https://www.google.com/";
constraints from "https://www.google.com/";
constraint from www.gnu.org
--8<---------------cut here---------------end--------------->8---
Notice the repeated "constraints from" directives.
