I was look at the back witch was off my new to me Seneca wp camera and noticed that there where groves on the inside the
back and one side had springs > what are these for / (splitter boards )
I had an 8x10 Kodak Commercial View Model B that had blacked glass half frame dividers that fit into groves like the ones you are asking about. One divider was horizontal and one was vertical, both , or neither could be used giving 4 - 4x5, 2 - 4x10, 2-5x8, or 1 - 8x10 image per sheet of 8x10 film. The dividers had the edges thinner than the rest of the glass.