It is an APS-C lens with an MFT mount attached to it. The focal length stays the same.
It will do the same thing as the existing Olympus 12mm f/2, or something similar to a 16mm lens on an APS-C camera, or a 24mm lens on a full frame camera. Similar, because the aspect ratios are not the same.
I would hold off to see how it performs. I doubt anyone has this lens yet.