This just in from ESA’s Mike Steinkopf at ATV-CC:

The ATV hatch was closed at 18:59 CEST, followed by the ISS hatch at 19:14 CEST. Now crew is performing the hatch leak check.

Before closure, the crew removed the gas masks and fire extinguisher, two smoke detectors, the cabin fan assembly, the Air Exchange Duct (AED – the big white hose thing – Ed.), lamp housing units and handrails. Some of these items are being stowed within Columbus to be used with the next ATV during ingress (fire extinguisher, gas masks, AED, handrails); others are spare parts for future ATVs (and also if the ISS needs, for example, the lamp housing unit).

In particular for this mission: the cabin fan was retrieved, which will serve as a spare fan for ATV 4.