What is python3mu?

I'm setting up PyDev for Eclipse, and I have to choose a version of Python for the interpretor. I want to use Python3, and I've been using python3 as my interpretor, so I thought /usr/bin/python3 would have been the obvious choice. However, another option there is python3mu. I ran this in the terminal and it seemed to function exactly like python3. My questions are: Which one is the correct one to use as the interpretor for Eclipse? and What is the difference between the two?

EDIT: Just wanted to let you guys know that my google-fu was not good enough to find out what python3mu was.

In python 3, some compile options (the abi flags) are reflected in the binary name and the name of cached bytecode in __pycache__ directories. mu means--with-pymalloc and --with-wide-unicode

See also http://docs.python.org/dev/library/sys#sys.abiflags and http://www.python.org/dev/peps/pep-3149/