Gee... I figured I would get this one wrong. It was so obvious that the question was not specifically including log files when the statement asked for database files, that the question was not, what are the extensions, but was the person writing the question going to be grouping log files with database files? Now I can see that the person is actually Microsoft and they call them database files. I call them log files. Same thing. So the question is now - is Microsoft right or me?
OK, Microsoft, I concede - you're bigger than I am.