Click through the links on that page.

I did. The links are giving me information about as useful as "a monad is a monoid in the category of endofunctors, what's the problem?".

In fact, your comment is about equally helpful. Ever heard the phrase "technically accurate but totally useless"? https://wiki.c2.com/?UselessTruth

Wherobots wrote a detailed tech review of the new types. You can find the definition and reasoning there: https://wherobots.com/iceberg-geo-technical-insights-and-imp...

Better. I still feel like there's an element of explanations there nearly as opaque as "a monad is a monoid in the category of endofunctors", but I can mostly forgive it. Clearly the review is written for someone already familiar with GIS terms. For example, "The geometry type represents spatial objects in a planar space using Cartesian geometry, assuming all calculations, including distance and area measurements, are performed on a flat surface." says nothing that couldn't be better stated as "this is for flat-projection maps, like the Mercator".