I use

sky130_ef_io__bare_pad.mag

in the standard library in

magic

. It is correctly treated as a subcell and I can see it as a subcell in the final .gds as well. However, after

extract all
ext2spice lvs
ext2spice

it disappears in the resulting .spice. I would expect it to show up as a .subckt just like other cells. Is there a way to fix this?

It has no devices, correct? Subckts with no devices are optimized out by default. You could set the LEFview property before extracting to keep it as an empty cell.

load sky130_ef_io__bare_pad -dereference
property LEFview true

Yes. there's no device in the cell. And your procedure works. Thanks. As far as I can tell, it adds

string LEFview true

into the file

sky130_ef_io__bare_pad.mag

.