Once again, code 2 means index finger print, digital picture and signature. These three will appear on your GC if only if your I485 is approved sometime later. Several month back code 2 was considered a good sign for I485 approval. It indeed means nothing now, it is just a regular procedure within the process. FYI, code 1 is ten finger prints, and code 3 is code 1 and code 2 conbined. Somehow these days there is another fancy name called biometics.
If you want more speculations regarding code 2, search this forum, I bet you will find tons of it. Good luck!!