Change history, and restoring a change
Every change to tasks is recorded as one entry you can read and restore -- from the app, the Gantt, a bulk edit, the AI, a workflow, a change request or an import.
What is recorded
Activity, Changes lists every change to the project's tasks: who made it, from where, when, and each field before and after. A change that touched many tasks at once -- a Gantt drag with its dependents, a bulk edit, an import -- is one entry. Filter by kind (edits, AI, automation, imports, restores) and by person.
Restoring
Restore puts back what a change did, including deleted tasks, their subitems and the dependency links the delete removed from other tasks. The restore is itself a change, so it can be undone too.
If something the change touched has been changed again since, Restore refuses and names what moved, so a newer edit is never overwritten without you knowing.