The WEBGL_lose_context.restoreContext() method is part of the WebGL API and allows you to simulate restoring the context of a WebGLRenderingContext object.
The ANGLE_instanced_arrays.drawArraysInstancedANGLE() method of the WebGL API renders primitives from array data like the gl.drawArrays() method. In addition, it can execute multiple instances of the range of elements.
The ANGLE_instanced_arrays.drawElementsInstancedANGLE() method of the WebGL API renders primitives from array data like the gl.drawElements() method. In addition, it can execute multiple instances of a set of elements.
The WebGLRenderingContext.compressedTexSubImage2D() method of the WebGL API specifies a two-dimensional sub-rectangle for a texture image in a compressed format.