Tripal Theme is a base theme and a collection of templates for the Tripal project. It is designed to provide minimal themeing with maximal customization of biological content through template files.
This theme is only applicable to Tripal for Drupal 6 versions. It is discontinued for Drupal 7 compatible versions of Tripal. Instead templates are provided with the Tripal package rather than via this separate base theme. And Tripal no longer requires a base theme.