What are the dll.response files and how to regenerate them?

I broke my game somehow and it won’t compile on windows anymore (it will for mac). I posted this question here: https://answers.unrealengine.com/questions/305054/how-do-i-debug-this-compile-error-filenotfoundexce.html

I was wondering what exactly are the dll.response files and how do we regenerate them?

You need to do Project > Rebuild, or delete your Binaries folder. I’m getting loads of trouble with these in 4.9, UBT must be crashing / hanging a lot…