Its what's usually called the UMC, it isn't really a wall connector, but some use it that way. Its intended to be plugged into an outlet and has a wide range of supported outlet types(but only one or two are supplied by default in the kit that comes with a 3).
Its limited to 32 amps, unlike the 48 amps supported by the hardwired 'real' wall connector.
[Edit]: it also looks like an older model UMC.