This extension is not distributed with Mercurial.
This extension provides a new command, digest, which creates a small summary of the nodes present in a repository. This file is easy to transport e.g. via email, and may be used as the target of an outgoing or bundle command to produce the set of changes in a repository which are not in the repository represented by the digest. For example:
$ cd stable $ hg digest ~/stable.digest $ cd ../devel $ hg bundle ~/to-stable.hg digest://~/stable.digest
Configure your .hgrc to enable the extension by adding following lines:
[extensions] digest = /path/to/digest.py