It is in equipment.gd and item.gd from revamp equipment and revamp item respectively for every icon far as I can tell
for example starting at line 19 of equipment.gd
#weapons
dagger = {
icon = input_handler.loadimage("user://mods/SFCRevamp/revamp_equipment/icons/Dagger.png"),
},
It is also SFCRevamp in all of the
icons\(item/equipment name).png.import
files for the two submods