In xfburn what's the 2TB disk?

In xfburn there is a drop-down to select your media and all the media are described except for the very last one. All it says is “2TB”.

I want to know a) what kind of (bluray?) disk is this, and b) who sells them.

Please no esoteric responses. A friend told me ten years ago that 1TB (bluray?) were around but I’d not heard of 2TB and I’d like to start using more sustainable media.

Perhaps this helps:

2020/II with MDisc support: ArchivistaBox & AVMultimedia with long-term archiving

look for this further down:

The only way to do this was with Xfburn, which is the smallest with about 8 MByte. Xfburn offers few but effective options and the tested version 0.5.5 is able to create BDR-XL with 100 GByte. The only thing you have to get used to is that you have to select the option 2 TByte when creating the image file.

So:
there is no 2TB optical media - this refers just to the process of image creation which is then to be written/burnt
that is how I understand this