The Devel add-on module for Drupal gives you a way to look at the impact of new modules. The module is useful during development of new modules because you can see the resources used. You can also use the Devel module during Web site development when you are comparting several modules or comparing options for a module.
There are threee modules in the package, Devel, Devel generate, and Devel node access.
Devel is the minimum you use during development and is required by the other Devel modules.
Devel generate generates test data, test users, test nodes, and test taxonomy terms.
Devel node access lists information about node access.