3.0rc3: List of 'os.', 'os.path.' attribute redundencies ... !! ?

IDLE 3.0rc3 (using XP) import os os.altsep '/' os.path.altsep '/' os.curdir '.' os.path.curdir '.' os.defpath '.;C:\\bin' os.path.defpath '.;C:\\bin' os.devnull 'nul' os.path.devnull 'nul' os.pardir '..' os.path.pardir '..' os.pathsep ';' os.path.pathsep ';' os.sep '\\'

3.0rc3: 'os.extsep' gone ... ?

IDLE 2.6 import os os.extsep '.' running XP this result is fine ... ! IDLE 3.0rc3 import os os.extsep Traceback (most recent call last): File pyshell#1, line 1, in module os.extsep AttributeError: 'module' object has no attribute 'extsep' why is this attribute gone in 3.0rc3 ? where