NEXT_ROOT directory structure?

[Marc Respass]

Can someone tell me what all the different folders are for in YB under the
NEXT_ROOT directory? They seem to be replicated in MXS. I have such a hard
time finding things. Is it /Library or /Local/Library? What's the
difference? There's /Developer and /Local/Developer. I don't get this
directory structure.

Thanks

--Marc Respass