zephyr_0.2_a2.5

The extrapolated (ExPO) model based on chujiezheng/zephyr_0.2 and alignment-handbook/zephyr-7b-sft-full, as in the "Weak-to-Strong Extrapolation Expedites Alignment" paper.

Specifically, we obtain this model by extrapolating from the weights of the SFT and DPO/RLHF checkpoints, achieving superior alignment with human preference.