The ANGLE_instanced_arrays extension is part of the WebGL API and allows to draw the same object, or groups of similar objects multiple times, if they share the same vertex data, primitive count and type.
The EXT_blend_minmax extension is part of the WebGL API and extends blending capabilities by adding two new blend equations: the minimum or maximum color components of the source and destination colors.
The EXT_disjoint_timer_query extension is part of the WebGL API and provides a way to measure the duration of a set of GL commands, without stalling the rendering pipeline.
The OES_vertex_array_object extension is part of the WebGL API and provides vertex array objects (VAOs) which encapsulate vertex array states. These objects keep pointers to vertex data and provide names for different sets of vertex data.
The WEBGL_debug_renderer_info extension is part of the WebGL API and exposes two constants with information about the graphics driver for debugging purposes.