Spine-WebGL
SkeletonDebugRenderer.ts
line 193-200

if (this.drawBones) {
   shapes.setColor(this.boneOriginColor);
   for (let i = 0, n = bones.length; i < n; i++) {
      let bone = bones[i];
      if (ignoredBones && ignoredBones.indexOf(bone.data.name) > -1) continue;
      shapes.circle(true, bone.worldX, bone.worldY, 3 * this.scale, SkeletonDebugRenderer.GREEN, 8);
   }
}

https://github.com/EsotericSoftware/spine-runtimes/blob/91a26443a9c42d78e45a5a50a19d411a4ccc7894/spine-ts/spine-webgl/src/SkeletonDebugRenderer.ts#L198

The shapes.circle method is always passing SkeletonDebugRenderer.GREEN color. I was expecting to be able to customize the boneOriginColor like boneLineColor property but it remained green during experimentation.