Docs: Update source-out policy note
Now that the full source-out policy has been implemented in the TCPMv2
DPM, modify the previous note about implementation.
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@@ -135,8 +135,9 @@ in-depth information can be found in the [USB Type-C Specification] \(section
### ChromeOS as Source - Policy for Type-C
-**Note:** Behavior outlined in this .md file reflects future-planned behavior,
-and is not present in the codebase currently.
+**Note:** Behavior outlined here is only implemented in the TCPMv2 Device
+Policy Manager (DPM) when a board defines a non-zero maximum number of 3A
+ports supported through `CONFIG_USB_PD_3A_PORTS`.
ChromeOS devices currently source power to external USB devices at 5V with a
typical current of 1.5A for each Type-C port. In certain scenarios, a Type-C
