Entity references is something we've talked about a bunch of times in the past, and even did a proof-of-concept at some point (#1487).

The general idea is that sometimes you really want a component to just be a reference to an existing component in another entity (or maybe even in the same one..??!).

Consider e.g. the case of a textured Mesh3D: you might want to add an AlbedoTexture component directly to that mesh (let's say it's e.g. a Tensor under the hood) or maybe you just want to point to an existing image-like thing that's already available in another entity.

Something akin to the following:

table Mesh {
  vertex_positions: [[float: 3]];
  vertex_colors: [uint] (nullable);
  vertex_normals: [[float: 3]] (nullable);

  indices: [u32] (nullable);

  albedo_texture: AlbedoTexture (nullable);
}

table AlbedoTexture {
  texture: _AlbedoTexture;
  vertex_uvs: [[float: 2]];
}

enum _AlbedoTexture {
  entity_path: EntityPath,
  tensor: Tensor,
}

No real plans yet, just something to keep in mind.