I've got a hunch that AI will be able to put Hyrum's Law (https://www.hyrumslaw.com https://www.hyrumslaw.com) to good use in the future: given an application,

I've got a hunch that AI will be able to put Hyrum's Law (https://www.hyrumslaw.com https://www.hyrumslaw.com) to good use in the future: given an application, generate unit tests for all documented and undocumented behaviours of the system. Do all the refactoring you need afterwards and you'll have a large safety net backing you up. With refactoring complete, regenerate unit tests for all new behaviours of the system.