Where are the docs for what args need to be added to amandad in
inetd.conf?

I added amindexd and amidxtaped on the backup server in order to do
amrecover, but then amcheck failed (needed noop, then selfcheck).
Then amdump failed (needed sendsize, ...).

I see the full list in amandad.c, and I think I understand why clients
don't need the addition.  It defaults to all services except amindexd
and amidxtaped being active.  But when you activate those two on the
server, it seems it _de_activates the others.

I didn't see it in the docs in the tarball and the wiki search leaves
a bit to be desired.  Where is it documented for the non-source diving
crowd?

Also, why would anyone want noop, selfcheck, sendbackup, etc.,
disabled?  Is it a use case that some people don't back up their
backup servers?

I've been using a 2.4.5 server for so long, I've missed some details.