@User: Yes, they are unitless, but this way we have a problem when we merge cells from several different libraries. When all libraries use the same unit, they can be used together on one design. With the SKY130 process, we currently have 3 libraries, SKY130 from Skywater, OSU130 from OSU and my LS130, so at least for those 3 we should define a common way to caculate the area attribute.