No, everything’s clear. The description is pretty detailed.
So, with “Discard all changes up to this checkpoint”, the chat rolls back, but the files stay modified. This is a separate bug from the diff issue. There are similar reports, like this one: Changes getting applied without asking, existing files getting deleted when undoing changes.
I’ve shared this with the team. For now, as a workaround, make a git commit before agent sessions so you can roll back with git checkout -- <file> or git stash.
Let me know if there’s anything else.