Well, I'm really not super well versed in conformal prediction, and I find the papers to be really hard to understand.
So, to the best my knowledge, our method is more similar to a bootstrap method (so I don't think we use any of the methods mentioned above).
You can refer to this paper:
https://arxiv.org/pdf/2109.12156
However, I think the implementation is more simplistic and not as robust as the actual methods described in the papers. That way, we get a good enough estimation and keep things fast.
We use the same method in all packages.
@Mariana Menchero, if I'm wrong, or if you have something to add, please let us know 😅