This is one that I had to go look up. Even my plane reference books didn’t list it but I finally found some information online. Apparently they have some use for creating a kerf specifically to help guide a saw for re=sawing and could see some function for establishing an easy to see line for thickness planning and for establishing a lip for raised panels, drawer bottoms, etc. If it was set up right I could see it also being used in place of a stair saw.There is a video online about a kerf plane build but if I was going to build one I would put an adjustable fence on the bottom like you find on a adjustable fence grooving plane, and would slot the saw blade so you can adjust the sawing depth like a stair saw. The possible drawback for re-sawing would be that resulting kerf would need to be close to that of the saw actually used for the re-sawing. It sounds like an excellent project and I hope you will post some photos of it. I may just build one myself.