Documentation: algorithm used for phasing in parabricks deepvariant

What algorithm is used for phasing in deepvariant when " --phase-reads" is used?
Which precisely is used for phasing and which is used for haplotagging? deepvariant - NVIDIA Docs

To clarify, I’m not interested in a detailed description… mainly, is it running whatshap under the hood? Right now I’m doing the Deepvariant-Whatshap-Deepvariant approach, using parabricks.