This shows that the full game installer was too large for a single file and was split into multiple compressed parts. You would need all parts (Part 1, Part 2, etc.) in the same folder to successfully extract the data.
This is the specific DLC (Downloadable Content) included, which added a new campaign, maps, and weapons to the base game. Aliens_Fireteam_Elite_Pathogen-FLT.part2.rar
This stands for FairLight , one of the oldest "Scene" groups known for releasing cracked games. This shows that the full game installer was