.FCM File Extension
File TypefCraft World File
What is an FCM file?
File created by fCraft, a third-party server program that hosts multiplayer worlds for the game Minecraft Classic; saves a map that represents the 3D world that players navigate in; hosted by the server and saved to the \maps\ directory on the server.
The FCM format is also the primary format used by Spacecraft, another third-party Minecraft Classic server.