I’m gonna jump in and try to clarify a couple of general things & terminology (not specific to Zev0’s product, but related-ish)—if I’m wrong about any of this please correct me!
We tend to use the terms “shader” and “shader preset” interchangeably around here, and most shader presets that are sold are placed in the “shaders” folder just to be confusing. But when someone is selling a new shader like Sheer Greatness or PW Toon or HSS Human Surface Shader, that is about which channels are available to apply to a surface - like, opacity, diffuse, specular, specular 2, velvet, refraction - not every shader has all the channels.
If you set up all the channels in a shader - blue diffuse, green specular, 50% opaque etc - and apply it to a surface, you can then save that in DS as a “shader preset.” If you save it in the shaders folder somewhere (like most of us vendors do!) it’s still a preset. (Confusing, I know!!!) It will apply the actual shader plus whatever you set on the channels. You can then apply that to any surface that you select, of anything. If your surface setting uses texture maps in any of the channels, it’s still a shader preset, but it won’t work without having the textures in the right locations.
A material preset saves some or all of the channels of your shaders specific to the material zones of a particular object, so it’s not quite the same as a shader preset. It can include multiple different shaders if they are applied to different mat zones.
DSON is the new file format that is used by DS that allows it to be read by plug-ins for other apps. In order to be read by Poser, there have to be “Poser companion files” and also you need the DSON importer on the poser side. So if a product says “1 DSON core installer” it just means it has the files in the new DSON format; if it says “1 Poser companion files installer,” that’s what tells you Poser can use it.