EGL_DEVICE_EXT not returned when query

@MikeRiches 
const char* s = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
	std::string platformExtensions(s);
	if (platformExtensions.find("EGL_EXT_device_base") == std::string::npos)
		std::cout << "error in EXT Device base";

I can not figure out why EGL_DEVICE_EXT  is not returned