What is time-travel-foundry?

Foundry Time Travel is a module for Foundry VTT, a popular virtual tabletop application used to run roleplaying games online. The module gives the Game Master (GM), the person running the game, a way to rewind an active combat encounter to an earlier saved checkpoint. If a battle goes badly, or the GM wants to replay a moment differently, they can step back in time to a recorded state and continue play from there. While combat is running, the module continuously captures checkpoints. Each checkpoint tracks a range of encounter data: turn changes, token movement on the map, which characters are participating in the fight, updates to character stats, item changes, active effects, and chat messages tied to the combatants. The GM can open a timeline panel to inspect all recorded checkpoints, choose one to review, and restore it to resume play from that point. The module is designed for Foundry VTT version 13 and newer. The scope in this first release is intentionally narrow: it covers only GM-facing controls, only active combat encounters, and only core Foundry document types. It does not promise perfect rollback in all situations, macro side effects may not be reversible, other installed modules may change state outside what is tracked, and world state outside the active combat encounter is out of scope. Custom game system support is planned for a later release. Installation uses a manifest URL pasted into Foundry's built-in module installer. The codebase is TypeScript, and the test suite enforces 100% code coverage.