@Fengrui Zuo I don’t think the sky130 standard cells have xschem schematic views at the current time. This might be a good project for someone or some school.
You can see the schematics for the standard cells in the skywater pdk repo.
For example here.
However, this does not contain the actual flip flop schematic. The cdl/spice file for the cells is in the same directory as the schematic screenshot.