AboutGlobal Robotic Response Unit XJ-X is a mysterious and newer member of the XJ android model series. At the end of the episode" Sibling Tsunami ", she is jokingly mentioned to Jenny and her sisters. She was planned to be in a movie of the series, but the film was never released.
In the episode "A Robot For All Seasons", Nora is seen reading the blueprints for her, before hiding them just as Jenny walks in the room, having begun its creation after she believed that Jenny had gone rogue, indicating that Nora would have either destroyed the "rogue" Jenny or stored her away along with her sisters after XJ-X's creation if Jenny had not been proven of her innocence. But considering that Jenny proved her innocence and efficiency at the end and that she had not gone rogue, it likely that Nora cancelled the XJ-X project.
Judging from the blueprints, XJ-X would have had a triangular build with more pointed features and crab-like claws.