What version are you running?
2.5.4
What's the URL of the page this enhancement relates to, if any?
.../r/
Describe the enhancement and the motivation for it.
It should be possible to render information in a review box based on data stored in the review's extra_data dictionary. Through front end hooks it is possible to populate the extra_data with UI in the review dialog etc, but there is no python hook for making use of this information.
There are a number of implementations which would solve this, such as:

1. Template hook points which will be evaluated for each review object, passing in the review data.

2. Some sort of field system similar to the ReviewRequestField setup which would allow rendering this information.

Currently Mozilla would like this since we are replacing the ship-it concept with the "review flag" concept used in bugzilla.mozilla.org (A reviewer is flagged for review [r?] and then may either approve [r+] dissaprove [r-] or remove the request [flag cleared]). We are able to make the UI modifications for the reviewer and properly store our flag information, but have resorted to a gross js hack in order to render this information as part of the review.