I'm trying to remember being a young Unix user but it was four decades ago, so the details become hazy. Nevertheless the proper go-to after the manpage fails to

I'm trying to remember being a young Unix user but it was four decades ago, so the details become hazy. Nevertheless the proper go-to after the manpage fails to clarify matters is the same as it ever was, that is, one reads the source code, if you have it, and this is easier today than ever.