Project Harbinger (IPA: /ˈhɑɹbɪnd͡ʒᶕ /) was a project-in-progress Armacham Technology Corporation is currently developing, involving an unknowing Sergeant Michael Becket and his Dark Signal squad.
The project itself is part of the Replica program designed to create psychic commanders without the use of Alma Wade. Inductees were fitted with several psychic amplifiers called "diodes", which were attached to the brain stem and spinal cord. During this procedure, the subjects were given several compounds used in Project Icarus to increase agility and strength. Once the subjects recovered, they were placed in the Telesthetic Attunment Chamber (TAC), which connected their mind to the target.
The project failed, however, as most subjects' brains were degraded from sensory overload, and turned into "Abominations". While they can control Replicas, they are not able to be controlled themselves.
As stated above, the majority of Dark Signal were identified as Harbinger candidates, but later on the purpose of Harbinger was changed by Genevieve Aristide from being able to command the Replicas, to being "bait" for Alma. It seems that Becket is the only known person to have actually fully survived the entire process in F.E.A.R. 2: Project Origin, explaining Alma's obsession with him and why Replicas around him activate and pursue him.
In F.E.A.R. 3, Paxton Fettel also mentions the project after he possesses Michael Becket at the Port Authority Airport to get information where his mother might be.