The map remembers the round
Planes fall, pilots bail, survivors get fished out of the sea — and now the ground keeps the receipts. Craters, burning crash sites, and oil slicks all stick around for the whole round, so the front line reads like a story of everything that happened on it.
Three kinds of scar
A bomb that lands on dry ground leaves a crater — a dark scorched bowl ringed with raised dirt, sized off the blast. A plane that goes in on land (whether it flew into a hill or corkscrewed down as a wreck) leaves a burning crash site: a charred skeleton with a smoke column that keeps going the rest of the round. And a hull that sinks leaves an oil slick spreading on the sea. They pile up as the round goes, so by the bell the map is a record of where the fighting was heaviest.
The one rule: don't touch the terrain
There's a hard constraint underneath all this. Warbirds' terrain is deterministic and shared — the server and every browser generate the exact same heightfield from the same math, down to the bit, which is how your plane collides with the same hill the server thinks is there. So a crater absolutely must not deform the ground: the moment the server carved a hole the client didn't (or vice versa), collision would desync and the whole thing would fall apart. Every scar is therefore a cosmetic decal laid on top of the pristine terrain — the server tracks a little list of them and tells clients where they are; the physics keeps sampling the untouched field. What you fly over is always exactly what the server collides against. (We ran the terrain bit-for-bit parity check to prove the ground never budged.)
Cheap by design
Scars never move, so they don't belong in the 20 Hz snapshot. They ride the join handshake (so a latecomer sees the round's history the moment they spawn) and a one-shot event each when they're made — reusing spare fields on the event we already send, for zero new wire format. The list is capped and wiped clean at the start of each round, so it can't grow without bound or bleed one round's carnage into the next.
With this the drama pass has closed its loop on death: the plane falls and burns, the pilot bails or gets fished out of the sea, and the crash site smoulders on the map behind them. Every kill now has a beginning, a middle, and an end you can still see minutes later.