help with relative imports

[John Salerno]

I'm reading the "What's New" section of the 2.5 docs, and I'm a little 
confused by the last section of "Absolute and Relative Imports":

-----------------------------------------------
For example, code in the A.B.C module can do:

from . import D                 # Imports A.B.D
from .. import E                # Imports A.E
from ..F import G               # Imports A.F.G
-----------------------------------------------

Can someone explain this? It seems like information is missing. How do 
you know where D, E, F and G are to figure this out? If all you are 
given is A.B.C, and then someone gives you the above three examples, 
what steps do you take to figure out what gets imported from where?

Thanks,
John