Sobras was the Delta Quadrant world where Captain Janeway and the Trabe leader Mabus gathered the Kazon first majes for peace talks in 2372, a meeting the Trabe tried to turn into a massacre.
Sobras is seen in the second-season episode Alliances. Worn down by repeated Kazon attacks, Janeway reluctantly seeks allies and befriends the Trabe, the Kazon's former oppressors, who now wander as refugees.
Mabus proposes a conference of all the sects, and the majes, among them Culluh of the Nistrim, agree to meet on Sobras. During the session a Trabe ship arrives outside the hall and opens fire through the windows, the real purpose of the gathering.
Janeway learns of the plot just in time and warns the room; Voyager drives the attacker away. The majes survive, but they now hate the Federation ship more than ever, and Janeway reaffirms her commitment to Starfleet principles.