The converter was declared public with a default constructor, so generic
Newtonsoft scanners (e.g. jillejr's newtonsoft-json-for-unity converters)
could pick it up and bind it into JsonConvert.DefaultSettings. Once
attached globally, any unrelated project code serializing a struct or
class containing a UnityEngine.Object reference would silently get an
asset path string back instead of the expected object JSON — purely from
having MCP for Unity installed.
Make the converter internal and expose Runtime internals to the Editor
and test assemblies via a Runtime AssemblyInfo so existing internal
consumers (UnityJsonSerializer, GameObjectSerializer) keep compiling.
Shutong Wu
c903626c3a