Their Oasis [1] board is going to use SiFive's IP, the main cluster is 12 P P670 cores, and 4 E cores. There are also 8 X280 cores as an "NPU", also RISC-V but with a slightly different ISA.
[0] - https://milkv.io/pioneer
[1] - https://community.milkv.io/t/introducing-the-milk-v-oasis-wi...