This is the ferry terminal for the IJplein ferry. For tourists this (free) line is not so important as there are no important tourist attractions at this side of Amsterdam North.
The ferry operates until midnight (after midnight you must use the Buiksloterweg Ferry).
The location of this terminal moved in 2014, a hundred meters or so to the East, so it is not right next to the Buiksloterwegveer and NDSM-veer.