On: glTF: Runtime asset format for WebGL, OpenGL ES, a...

[wolfgke]

According to the text

  a glTF asset is represented by:
  * JSON file (.json) containing the node hierarchy, materials, and cameras
  * Binary files (.bin) containing geometry and animations
  * Image files (.jpg, .png, etc.) for textures
  * GLSL text files (.glsl) for GLSL source code for individual stages

See also https://github.com/KhronosGroup/glTF/tree/master/model/duck for an example.