Minecraft wiki entry for RenderDragon, associated text: "From what I've seen so far, there's currently nothing in RenderDragon that indicates it is usable in the Java codebase. I'm not convinced it would be good for RenderDragon if Java Edition used it, for now it's best we don't pollute RenderDragon with Java Edition's many issues." – @Xilefian on Twitter, March 10, 2021