Any change that you make to your data in OpenRefine can be undone, and is documented and numbered from when you first create your project. Use the Undo/Redo option to change any action, or to change a group of actions you have performed on this data.
Your operational history is saved along with your data as part of your project. Quitting OpenRefine and reopening your project does not disturb the operational history. Operational history can also be extracted and applied to additional datasets.
Note, edits modifying the contents of a specific, single cell are not captured in the operational history.
You can copy and export your change history (every edit you have made to your data since creating a project). This is particularly useful if you are working on batches of files that will all require the same changes. To export your change history, look for the option just below the Undo/Redo tab.