Projectile data is hardcoded in Dark Forces but the data has been externalised to a JSON file in The Force Engine. The data is located in ExternalData\DarkForces\projectiles.json.
Altering the data in projectiles.json will alter the way that weapon projectiles behave in the game. If the JSON file is removed, renamed or corrupted, weapons will not work correctly. (In this case, an error message will be logged to the TFE console when loading the game.)
Mods
A customised version of projectiles.json can be included in a mod's ZIP file. A modded projectiles.json will take precedence over the original.