The most important information to capture in the audit log of an application hosting personal data is the last user who accessed personal data. This is because the audit log is a record of the activities and events that occur within the application, such as user actions, system events, errors, or exceptions. The audit log helps to monitor and verify the compliance, security, and performance of the application, as well as to detect and investigate any incidents or anomalies. Capturing the last user who accessed personal data in the audit log helps to ensure the accountability and traceability of the data access, as well as to identify and prevent any unauthorized or inappropriate use, disclosure, or modification of personal data.