Are EGL extensions that were promoted to core (like EXT_platform_base & EXT_client_extensions were in EGL 1.5) still exposed via the EGL_EXTENSIONS string?
I wasn't seeing anything obvious either way in section 2.8 of the EGL 1.5 spec ("Extensions").
I did turn up this on the OpenGL Registry repository but there's no indication that it might cross-apply to EGL.