Reply-Code Alpha

Reply-Code Alpha is a signal that Algalon the Observer could send to the Titans, signaling all is well on Azeroth. According to the Archivum Console of Ulduar, Reply-Code Alpha is one of two possible reply signals following by planetary diagnostics after the arrival of Algalon. The chance of Algalon sending such a signal is nearly 0%.

This item starts the quest All Is Well That Ends Well.

Source
This item can be looted from the Gift of the Observer after defeating Algalon the Observer in the 10-man version of Ulduar.