https://fabiensanglard.net/gebbdoom/
When I upload the PDF on Amazon, a minimal price is automatically calculated. In the case of the DOOM, Amazon sets the minimal price at $51.35.
There is a slider which authors can use in order to add their "share" on top of Amazon price. I have added $3.88 which Amazon also takes a cut on. The result is $1.59 royalty and $0.77 profit per book sold.
Amazon: 40% of the price
Author: 3% of the price (half of which goes to taxes)
Color printed books are expensive, but I think he chose the premium color print option rather than the standard color print option. You can try it out: https://kdp.amazon.com/en_US/royalty-calculator { pages: 432, dimensions: 7.5"x9.25" } Roughly $18 for basic color and $36 for premium color (which probably also means heavier, higher quality paper).
Amazon takes 40%. Barnes and Noble Press takes 45% for self-published books, and their printing costs are within a couple dollars. Compare to typical retailer+distributor costs of >50% while authors get <15%.
The economics of retail print publishing and logistics don't seem to work out at higher author royalty rates. Authors who don't want to give up 40% of list price always have the option to handle printing, shipping, and accounting themselves, selling on ebay or from their own website.