This is the code review system, Critic.
Critic has a few concepts that might be useful to know.
To install Critic, run the script install.py as root:
# python install.py
It will ask a number of questions and then perform the installation.
You should probably read the INSTALL file for all the information.
After installing you should be able to navigate to the hostname you specified during installtion and see Critic running. When using the administrator account you will also see 'Repositories' and 'Services' as top level menu items, in addition to the usual menu items. To add a new repository, click the 'Repositories' menu item and then the 'Add Repository' button in the top right corner.
Before a user can push review branches to the newly created Critic repository their account must be a member of the 'critic' system group (or whatever group name was chosen during installation). In Debian/Ubuntu this can be done using:
usermod -a -G critic <user-who-wants-push-rights>
The developers responsible for performing the code review can subscribe to new review requests either for a specific set of subdirectories or for the entire source tree. This configuration is done by each reviewer under the 'Home' top level menu item.
For information about how to request a new code review, click the 'Tutorial' top level menu item, and then select 'Requesting a Review'.
The Critic user FAQ answers some common questions and gives some useful tips on how to use Critic efficiently.