Layer:purpose 70:13 us a metal3 resistor. There is, unfortunately, rather a lot of confusion around layer:purpose values. The earlier DRC decks for the s8 process had purpose 15 = "short" and purpose 14 = "cut". I have never figured out what the difference is (or if there is any). There is a transistional document between s8 and sky130 that lists the generic purpose 13 = "type resistor (for diff, poly, wells, and metals)", and which does not list purposes 14 and 15 at all. Based on the transitional document, I implemented purpose 13 for all metal layers as "metal resistor".