There is no such thing. You will use a higher percentage of rye flour in pumpernickel bread, and to get the very dark color, I use a combination of cocoa powder and instant espresso powder.
There are commercially available flours called "pumpernickel flour" but it is not a standardized term. From the Laurel's Kitchen Bread Book, "'Rye meal' and 'pumpernickel flour' are sometimes whole grain, but you can't count on it." Look at a range of recipes for an ingredient list that sounds like pumpernickel to you. She also talks about the various names for rye flour, which are confusing, and don't mean what they sound like. (It's a Gilbert and Sullivan world!)