What Amanda command *uses* Application API 'index' operation?

Hi,

This may be a silly question where I've just overlooked something
obvious, but ...

The Application API specifies an 'index' operation, able to read
through an existing dump stream and emit the same index information
that might have been created by the 'backup' operation at the time
the dump was made.

That seems like it could be useful in case of some failure that
messes up the retained index info on disk. I'd assume there's some
Amanda top-level command for doing that, which would look up the
DLE info and spawn the right application in 'index' mode and
recreate the index. But is there? Maybe it's an option I've
missed to some other command like amfetchdump?

Where should I look?

Thanks,
-Chap