The primary release platform is usually the (official forum) or Polish OMSI community sites like „Omnibussimulator.pl” or „Marcin’s OMSI Workshop” . Search for: "OMSI 2 Fikcyjny Szczecin 3.0 download"
: Look for the thread by user MrYanke$ on Strefa OMSI for the most authentic version and updates. Omsi 2 Fikcyjny Szczecin 3.0 Download