For more information, see the associated wiki page
References are excluded from this repo, but you can source them from the following directories. These do not need to be included with the built library, if injected into a process with the same assemblies.
...\Pillars of Eternity II\PillarsOfEternityII_Data\Managed\Assembly-CSharp.dll...\Pillars of Eternity II\PillarsOfEternityII_Data\Managed\UnityEngine.dll