Econ
Econ system is referenced around the 
Source SDK. Econ is short for Economy.
The Econ system is used to create items, such as wearables for the player.
Counter-Strike 2
In 
Counter-Strike 2 there's specifically a filetype named .econitem for configuration, utilized from the Workshop Item Editor. It is also the main component file for the upload of Weapon Finishes on the Workshop.
