I like to have an official place where the build rules and artifacts are clearly laid out. I don't think file system directories are a good place to put the tru

I like to have an official place where the build rules and artifacts are clearly laid out. I don't think file system directories are a good place to put the truth. For one thing, parsing the information from the directory contents means relying on out-of-band data. For another, directories often contain files that "should not be there". Or maybe you accidentally delete an important file. The build couldn't detect the mistake.