The EXT_color_buffer_half_float extension is part of the WebGL API and adds the ability to render to 16-bit floating-point color buffers.
WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.
Note: This extension is available to both, WebGL1 and WebGL2 contexts. On WebGL 2, it's an alternative to using the EXT_color_buffer_float extension on platforms that support 16-bit floating point render targets but not 32-bit floating point render targets.
The OES_texture_half_float extension implicitly enables this extension.