Decor and furniture
Sign Canvas Corrugated Metal 4x3
It's a sign. You write things on it.
Harvest drops
Iron× 10
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
When it collapses
Falling, it leaves 
Scrap Metal Pile (60% of the time) where it lands.
Where to find (4 POIs)
Shamway Factory (tier 5), Hybrid Energy (tier 4), Hybrid Energy Substation #1 (tier 3), Shady Rest Area.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.