The audit trail collects and logs all of the changes made to a contract.
It can be found in the top right corner of the contract.
Click on it to open a detailed view.
Here you can see a collected "history" of the contract from start to finish. If you click "Show details" you can see the exact change that was made. If you click the underlined time you will see the exact date and time of the edit.
The audit trail is considered a part of the contract and is added to the contract PDF in its entirety.
Note: The timestamp in the audit trail will be registered in timezone CET while the time stamp in the PDF will be registered in timezone UTC. This to ease global use of the PDF.