its an mdx1000 model. it is an SD model but its made with ingame textures that only exist on reforged and its formatted in the reforged SD format. Convert to classic SD format if you want to view it. Alternatively, just try previewing it on
Sanity Test which supports the new format unlike dated tools like Magos/Mdlvis.
Edit:
to be honest, it's mostly just birth/detail SD animationset from the barracks added to the Reforged thrall's hut model. It's mostly a joke.