Tabletop Simulator (or TTS) is a computer program used for simulating and playing all manner of tabletop games.
It has been a consideration for porting Mondo Megabits gameplay, but personally I think it has too much excess given what this project needs.
TTS brings some bloat with it to simulate the environment physics and things on the table, which we don’t need when just testing card rules. It also seems harder to update, whereas Cockatrice uses just a text file that I can edit and post online.