One of the function that exist deep down in the AActor class is CheckForErrors. This function is being executed for every single instance of the class that has it implemented when a Map Check is executed.
Now, what is a Map Check you may ask. Well, this is a button inside the editor under `Build` menu, see screenshot below.
Once its pressed, a script is going to iterate over all actors on the current map and execute CheckForErrors function. It will then report all warnings and errors in the message log which was the topic of the yesterday's daily unreal column.



