Corys fix helped. Wonderful. Thanks!

http://www.debian.org/doc/debian-policy/ch-relationships.html#s-replaces

I'm testing the proposed fix.

Cory points to this documentation: http://www.debian.org/doc/debian-policy/ch-
relationships.html#s-replaces

(Naturally, this is only an issue when upgrading from the previous version 
(2.12.x).)

When updating the mirrorbrain packages on Ubuntu or Debian systems, the upgrade does not 
complete upon the first attempt. The problem is that the file /usr/bin/mb has been moved to a 
different subpackage, and apt-get doesn't want to overwrite it:


Unpacking replacement python-mb ...
dpkg: error processing /var/cache/apt/archives/python-mb_2.13.0-3_amd64.deb (--unpack):
 trying to overwrite `/usr/bin/mb', which is also in package mirrorbrain-tools
Preparing to replace mirrorbrain-tools 2.12.0-2 (using .../mirrorbrain-tools_2.13.0-
3_amd64.deb) ...
Unpacking replacement mirrorbrain-tools ...
Processing triggers for python-support ...
Errors were encountered while processing:
 /var/cache/apt/archives/python-mb_2.13.0-3_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)



To complete the update, it is necessary to run 'apt-get upgrade' a second time. 

This may be a packaging error; I'm not sure how to solve it right now.