Debugging CI 3 using Firefox, Firebug, and firePHP?

In trying to set up a resource for debugging CI 3, I have installed Firefox and the add-ons Firebug and firePHP. But I have not been able to find enough information about the required server-side firePHP library and its installation. The firePHP project lies in https://github.com/firephp/firephp , but the documentation links are unresponsive. I wonder if this project is still current.
If anybody in the CI community has traveled this path, I shall appreciate any pointers as to how to access the firePHP library and its documentation. Thanks a lot.