Just the same as if someone finds a bug in Boost. It is hard to understand. It is efficient. It probably requires computer science knowledge to solve the issue

Just the same as if someone finds a bug in Boost. It is hard to understand. It is efficient. It probably requires computer science knowledge to solve the issue. And yet it is as maintainable and well documented as they possibly can make it. Not everything can be 'business logic' in the sense of 'something a manager can understand but not code'. Some algorithms are just hard. And they are worth it. What would be Google without PageRank? What would be Skype without their LAN piercing modules? What would be iD without their game engines? What would be CryTek without their game engines? Worthless, that's the answer.