i wonder what those 2 files are?

1. in the english version is an extra tracks installer?

2. and in the bonus section is a optionaöl win version installer?

what are those for? :)

That's the Windows version (as opposed to the main installer which has DOS version + Dosbox). See the sticky thread:
http://www.gog.com/forum/heroes_of_might_and_magic_series/heroes_of_might_and_magic_2_gold_windows_version_available_as_an_extra_please_read I *think* it has the original tracks (the main installer uses the PoL tracks). Or vice versa. I could be mistaken here since I don't own the game on GOG.