Final answer:
Functional supersession applies to maintenance keys and technical manuals, indicating that newer versions have replaced older versions while still serving the same purpose.
Step-by-step explanation:
The supersession that applies to maintenance keys and technical manuals is functional supersession.
Functional supersession occurs when a newer version of a product or component has replaced an older version, and the newer version is designed to perform the same or improved function as the older version.
In the context of maintenance keys and technical manuals, functional supersession means that newer keys and manuals have been developed to replace older ones while still serving the same purpose of providing access to a device or offering instructions for its maintenance.