This is a Drupal module that replaces some Drupal core theme functions with more extensible and backwards compatible versions.
This is a utility module. If no other module you want to have installed requires this you don’t need it.
- Drupal 7.x
No, themes can’t implement hook_theme_registry_alter()
which is used for implementing the changes. Also having this in a module makes it possible for other modules to depend on it.
Getting such changes merged into Drupal 7.x was barely possible in 2012 (shortly after it was released). It’s near impossible now (2020).