BfilesExtension
This extension is not distributed with Mercurial
Author: Greg Ward <greg at gerg dot ca>
Repository: http://hg.gerg.ca/hg-bfiles
bfiles is a Mercurial extension for handling large binary files.
User documentation: usage.txt
Design documentation: design.txt
For a different approach to the same problem, see HgExternalBinaries
LargefilesExtension took this extension as base and is distributed with mercurial-2.0. You may also have interest in SnapExtension and BigfilesExtension.