@User It's in the

sky130_fd_io.spice

file.

* Modified by Tim:  The resistors here are in an annular shape, and they overlap
* between cells such that the center of the resistor connects between the two
* devices.  To be correct, these two nets must come out as pins.

.SUBCKT sky130_fd_io__signal_5_sym_hv_local_5term GATE IN NBODY NWELLRING VGND net16
*.PININFO GATE:I IN:B NBODY:B NWELLRING:B VGND:B
XI1 IN GATE VGND NBODY sky130_fd_pr__esd_nfet_g5v0d10v5 m=1 w=5.4 l=0.6 mult=1
+ sa=0.0 sb=0.0 sd=0.0 topography=normal area=0.048 perim=0.94
* RI9 net18 NBODY short
* RI8 net16 NWELLRING short
RI9 net18 NBODY sky130_fd_pr__res_generic_m1
RI8 net16 NWELLRING sky130_fd_pr__res_generic_m1
.ENDS sky130_fd_io__signal_5_sym_hv_local_5term

Looks like you (or some other Tim) added

net16

to the pin list. Two of the calling subcircuits,

sky130_fd_io__gpio_buf_localesd

and

sky130_fd_io__gpio_buf_localesd

, have also been modified, but looks like there was one more.

.SUBCKT sky130_fd_io__gpio_ovtv2_hotswap_pghs_i2c_fix EN_H FORCE_H[1] OD_I_H_N
+ P3OUT PAD PADLO PGHS_H TIE_HI VCC_IO_SOFT VDDIO VPB_DRVR VPWR_KA VSSD
*.PININFO EN_H:I FORCE_H[1]:I OD_I_H_N:I P3OUT:O PAD:I PADLO:O
*.PININFO PGHS_H:O TIE_HI:I VCC_IO_SOFT:I VDDIO:I VPB_DRVR:I VPWR_KA:I
*.PININFO VSSD:I
Xhsctl_q0 EN_H enhs_lat_h_n FORCE_H[1] OD_I_H_N P3OUT PAD net50 VDDIO VPB_DRVR
+ VPWR_KA VSSD sky130_fd_io__gpio_ovtv2_hotswap_ctl_i2c_fix
XI3 enhs_latbuf_h_n PADLO sky130_fd_io__sio_tk_em1s
XEpghs12 PGHS_H net54 sky130_fd_io__sio_tk_em1o
XI2 enhs_lat_h enhs_latbuf_h_n VSSD VSSD VDDIO VDDIO
+ sky130_fd_io__sio_hvsbt_inv_x4
XI1 enhs_lat_h_n enhs_lat_h VSSD VSSD VDDIO VDDIO sky130_fd_io__sio_hvsbt_inv_x1
Xpghspu_q0 PAD PGHS_H net50 TIE_HI VCC_IO_SOFT VPB_DRVR
+ sky130_fd_io__gpio_ovtv2_hotswap_pghspu
Xclamp_q0 VSSD VDDIO VSSD VDDIO PAD sky130_fd_io__signal_5_sym_hv_local_5term
*                                   =========================================
Xpghs12_q0 net54 PADLO VPB_DRVR VPB_DRVR sky130_fd_pr__pfet_g5v0d10v5 m=1 w=3.0
+ l=1.0 mult=1 sa=0.265 sb=0.265 sd=0.28 topography=normal area=0.063 perim=1.14
.ENDS sky130_fd_io__gpio_ovtv2_hotswap_pghs_i2c_fix

I think it's sufficient to add a

VDDIO

connection after

PAD

. Maybe it's not used in caravel, though.