The Jedi Initiate is a Universal Specialization.
When the Jedi Order was still around, children from all over the galaxy were brought to the temple to begin their training. Here, they learned the basics of the Force, and began their training as a youngling. When they were ready, they were taken by a knowledgeable Jedi Knight or Jedi Master as a Padawan. These initiates learned the skills that would be necessary for their trials of Knighthood.
By the time of the Galactic Civil War, however, few Jedi remained to train prospective force users in the skills necessary for the Jedi Trials. Those few lucky enough to find masters capable of teaching them may benefit from the wisdom and power of this rare specialization.
The Jedi Initiate can be found here.