XTEN Harbinger Attachment Guide
The XTEN Harbinger attachment in Call of Duty: Modern Warfare 2 and Warzone 2 is Weapons Platform Specific. In other words, this weapon barrel is exclusive to a particular family of weapons.
How to Get the XTEN Harbinger
To unlock the XTEN Harbinger attachment in Call of Duty: Warzone 2.0, you need to upgrade the P890 to Level 25.