ISO3166-2 Field

This area seems to have the wrong province code, “IG-ST”, should be “ID-ST” I think.

Is this something users can contribute with… I don’t see an edit function?

Where did you get this data from ?
When you go to osm.org, and search for Central Sulawesi, you will be taken to http://www.openstreetmap.org/relation/2388664#map=7/-0.934/121.915

When you have an account, you’ll see the edit button at the top. It’s greyed out because you have to zoom in before you can start editing. Zoom in, make sure you keep seeing the red line, until the zoom button gets enabled. Click the edit button.
Perhaps you have to zoom in even more. At a certain point you’ll see the dashed line representing the border.

Click it, on the left you see all it’s properties. Scroll down, to the All Relations section.
Click on “Administrative Boundary Central Sulawesi”
Then you see all tags for that relation, scroll down to “All tags”, there you find the ISO code.
Change its value and save.
Don’t forget a good changeset comment (which source are you using for the change local-knowledge or wikipedia or …)

Thank you! It worked exactly you as described. The data is from the Overpass API.