Operation Blue Plug was an operation planned by General Garm Bel Iblis to retake the key system of Commenor, following the New Republic's recapture of Coruscant. The plan was never put into motion because the people of Commenor ousted the Imperial governor on their own a short time later.
The entire plan was quietly classified and forgotten until about 40 ABY, during the Second Galactic Civil War, when it was claimed in the Chasin Document that the Galactic Alliance was planning to invade Commenor. Tycho Celchu, being familiar with some of the tactics used by Bel Iblis, became suspicious that the Chasin Document was actually a revision of Blue Plug. He asked his wife, Winter Celchu, to conduct an investigation to determine if the still-classified Blue Plug documents had been sliced into. Winter discovered that the Alliance's backup code had indeed been sliced using a Galactic Alliance Guard passcode and had been altered to send files to a spy. The military networks were scrubbed of the spy's code, and Winter's findings were turned over to Galactic Alliance Intelligence Service. Tycho and Winter presented their findings to a group of Galactic Alliance military personnel, including Admiral Niathal and Colonel Jacen Solo, who was infuriated about the implication of GAG in the security breach. Upon checking the code in his datapad, however, he determined that the passcode was on a list of unassigned passcodes.