The file sent from the Host to the player. A RST file contains the universe as seen by the player. Players can unpack it and play, to finally produce a TRN file they send back to the host.

RST files contain planets, ships, starbases, messages and combat recordings, plus some administrative information such as the scores. When you play with Winplan, you'll also get ion storms, minefields and explosions in your RST. The RST does not contain the ship list, nor the starchart.

PHost also sends a file UTILx.DAT to each player which contains the subspace messages in a machine-readable format.