The artwork for natural tiles of steel were never updated, and are still marked in-game with "Looks like silver, update me".
I discovered this while making a nature reserve out of melted steel, and cooling it to form natural tile flooring, because I could, and noticed some odd text in the artwork of the tiles.
Image attached, it's odd. Recreated in a debug sandbox because it was easier to show the full text
Steps to Reproduce
Create natural tiles of steel, either by melting/cooling steel into natural tiles or by debug, observe.
This issue has been fixed in either a future version or updated in a previous version.