Covid test requirements for teens/children, when crossing by land into the US from Mexico

In November 2021 the US/Mexico border re-opened for fully vaccinated non-essential travelers. According to this page there is no testing requirement if crossing into the US by land.

However, the "fully vaccinated" requirement is only for adults 18 years and older. Children and teens under 18 don't currently have to be vaccinated if crossing the border with a fully vaccinated adult.

Which raises the question, do these children/teens need to provide a negative test at the land port-of-entry to be admitted into the US, since they aren't vaccinated?

*Note that this is asking specifically about non-essential travelers - ie not US citizens, residents, workers etc. who have a different set of requirements that nobody in my family qualify for.