Which type of S3 Object Lock remains until explicitly removed?

The type of S3 Object Lock that remains until explicitly removed is the Legal Hold. A Legal Hold is used when there is a need to preserve data for legal or compliance reasons and does not have a defined retention period. It can only be removed through an explicit action, making it essential for situations where data must be safeguarded against any modifications or deletions until a predetermined condition is met or until a legal directive is lifted.

In contrast, the other types of Object Lock have different characteristics. Retention Period specifies a duration during which an object is protected from deletion, and once this period expires, the object can be deleted or modified. Governance Mode allows users with specific permissions to alter or delete objects, while Compliance Mode ensures that objects cannot be deleted or altered for the specified retention period, but it doesn't provide the indefinite hold that a Legal Hold does.