Imac late 2015

Hello,

I have this iMac late 2015.The 16,2 21 inch Retina. Once thing I just do not understand. In system overview over the iMac I find information about the hardware. There I see Thunderbolt/USB4

Why it is there? As far as I know this Mac has Thunderbold2 and USB3 ports. Can someone explain me this.

And what is USB4? Is this the same as Thunderbolt? It is in Dutch, but I think you will understand this picture blow

See below.

Thank's Richard