The WebGLQuery interface is part of the WebGL 2 API and provides ways to asynchronously query for information. By default, occlusion queries and primitive queries are available.
The WebGLTransformFeedback interface is part of the WebGL 2 API and enables transform feedback, which is the process of capturing primitives generated by vertex processing. It allows to preserve the post-transform rendering state of an object and resubmit this data multiple times.
The WebGLVertexArrayObjectOES interface is part of the WebGLOES_vertex_array_object extension, represents vertex array objects (VAOs) pointing to vertex array data and provides names for different sets of vertex data.
The EXT_disjoint_timer_query.createQueryEXT() method of the WebGL API creates and initializes WebGLTimerQueryEXT objects, which track the time needed to fully complete a set of GL commands.
The OES_vertex_array_object.createVertexArrayOES() method of the WebGL API creates and initializes a WebGLVertexArrayObjectOES object that represents a vertex array object (VAO) pointing to vertex array data and which provides names for different sets of vertex data.