It's the air conditioner. Airstair doors usually indicate that it was a VIP helicopter and an air conditioner was an option. We had a similar thing on a 332L1 bought from a large company. The view through the main cabin suggests that the rear airstair door that goes under the boom was also there.
The 332 has taken a caning because of the troubles with the 225. It has no value in the offshore market and there is not a lot else.