“The script can convert most models and plugins from both Fallout 3 and Fallout: New Vegas, as well as the base game of New Vegas, from their native game engine of Gamebryo. “
It’s definitely written very stupid. The only thing that makes sense is that they are using different builds for FO: New Vegas with all DLC, and maybe the basic un-updated version of FO:New Vegas? Tbh I just assumed it was something that was helped with AI and it didn’t get caught by editing.
Edit-looking at another comment that linked the Nexus page, it looks like they are taking about the base game of New Vegas being ported into the Fallout 4 engine, and the assets from both games. Worded terribly for sure.