Files with dec extension can be also encountered as deck databases for computer version of Magic: The Gathering Online a computer game.
DEC file extension - Magic: The Gathering deck of cards
What is dec file? How to open dec files?
File type specification:
File extension dec is also associated with the Magic: The Gathering Online a computer variant of card game Magic: The Gathering.
A .dec file from this game contains database of cards for editor implemented in the game client.
List of recommended software applications associated to the .dec file extension
Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open dec file, edit dec file, convert dec file, view dec file, play dec file etc. (if exist software for corresponding action in File-Extensions.org's database).
Unspecified and all other actions for computer programs working with dec file - Magic: The Gathering deck of cards
Click on the software link for more information about Magic: The Gathering Online. Magic: The Gathering Online uses dec file type for its internal purposes and/or also by different way than common edit or open file actions (eg. to install/execute/support an application itself, to store application or user data, configure program etc.).