@Sorgelig : why do you write that the microcode isn't open to public ?
The sources contains the hdl source file that implements the "sequencer" (MCL65.v) and the code for the 6502 written in microcodes (both the "binary" and the disassembled code : microcode_rom.hex).
And in all the files there is the same copyright notice :
// Copyright (C) 2017 by Ted Fried info@MicroCoreLabs.com
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose and without fee is hereby granted, provided
// that the above copyright notice appear in all copies and that both that
// copyright notice and this permission notice appear in supporting documentation.
// This software is provided "as is" without express or implied warranty.