It's dry, full of fiber, and resembles roofing tiles -- but the main problem is that it's too often contaminated with excessive amounts of aflatoxin.
See: https://www.feedipedia.org/node/699
Current market price is around $350/ton, though, which makes it one of the cheapest protein sources around...
Edited to add: There's also soybean oil cake, sunflower oil cake, and others. Sunflower cake might be interesting as a low cost food/protein supplement in humans.
Not sure it is fully identical, but you can purchase peanut powder in stores. It is effectively powdered peanut butter. Tastes fine, but it seems like it would be tough to make a meal out of it. More a supplemental protein source you can mix into other foods. I last bought some years ago, but a tub of the stuff was very affordable.
