What version of Slic3r is used?

The Slic3r announcement https://www.mosaicmfg.com/blogs/technolo...
indicates that the code was used ‘without making any modifications to it’ and they go on to thank Prusa research.

I can’t find a slic4r or prusaslicer fork in their code repository, so I guess that is the ‘without modifications’ part?

So does anyone know if it is the latest prusaslicer 2.4? I know canvas says Slic3r, but I would guess that they would say that even if they were using the prusaslicer fork?