Finally back to my computer.
So a few options have been presented for unfolding or unwrapping. No matter which one you use, they will only unwrap a surface so you can’t flatten out the bent part with thickness as in your model. For something as simple as this piece I wouldn’t bother to unfold it. I figured out the centerline of the edge, found its length–Entity Info will tell you that-- and drew a rectangle to which I added the radiused corners and hole. I also added some softened edges to show where the bends are. I expect they aren’t really needed, though.
CBBD000.skp (106.8 KB)