Jaret was a Sikarian civilian who secretly offered Voyager's crew the trajector in exchange for their library of literature.
Jaret was a Sikarian who, unlike the magistrate Gath, was willing to break his people's law against sharing technology. He approached Harry Kim with an offer to hand over a trajector in return for Voyager's collection of stories, which the Sikarians valued highly.
In Prime Factors, the illicit exchange was eventually made by Tuvok, who beamed down without telling Janeway. The device turned out to depend on the crystalline mantle of the Sikarian homeworld as an amplifier, so it could not work once the ship left orbit, and an attempt to use it nearly caused a warp core breach.