UniG2U-Bench: Do Unified Models Advance Multimodal Understanding? - Zimo Wen; Boxiu Li; Wanbo Zhang; Junxiang Lei; Xiaoyu Chen; Yijia Fan; Qi Zhang 066; Yujiang Wang 010; Lili Qiu; Bo Li; Ziwei Liu 002; Caihua Shan; et al. (CoRR, 2026)