Jentari were "manufactories" on Zonama Sekot who produced living seed ships. They were genetically-engineered cyborgs.
The Jentari—"the makers of Sekot"—were huge cybernetic organisms that were bred by the Magisters of Zonama Sekot to be factories on the living planet. They were tree-like creatures that understood the needs of Sekot and channeled the world's energy into the constructs that were built within them. With "thick green and purple trunks, gleams of metal, glints of other artificial substances, supplements, add-ons," these giant organisms were involved with complex tasks involving the delicate, fluid shaping of Zonama Sekotan ships, which included Sekotan personal starships.
Xenobiologists believed that the Jentari were responsible for the creation of boras and the tampasi. The original Magister of Zonama Sekot used to refer to them as Shapers.
During the Yuuzhan Vong War, Zonama Sekot was forced to make a blind hyperspace jump in order to avoid the sabotage done to its hyperdrives by Nom Anor. As a result of this, the planet suffered a great deal of trauma on its surface forcing the Ferroans to flee underground to avoid the ecological damage while the Jentari themselves went into hiding.
The reference of the Jentari as Shapers links them to the Yuuzhan Vong as part of their shared origin.
- The Complete Star Wars Encyclopedia