(About Aux-Items): Reduce the amount of text talking about aux-items

	on persons.
(Aux-Item Inheritance): New node.

doc/Protocol-A.texi

@@ -744,6 +744,7 @@ server and in protocol A.
 
 @menu
 * About Aux-Items::             An introduction to aux-items.
+* Aux-Item Inheritance::        Comments can inherit aux items.
 * Predefined Aux-Item Types::   Predefined aux-items are part of the protocol.
 * Client-Specific Aux-Item Types::  Clients can allocate aux-items for
                                     their private use.
@@ -757,10 +758,8 @@ server and in protocol A.
 
 Aux-items were introduced in protocol version 10 as a mechanism for
 extending the conference, text and server information structures without
-changing the protocol.  Persons were excluded since nobody could figure
-out a case where setting an aux-item on the mailbox wasn't as good as
-setting it on the person (another reason was that I was fed up writing
-aux-item code by the time they were working on texts and conferences.)
+changing the protocol.  (There is no need for aux-items on persons --
+just add an aux-item to the corresponding mailbox.)
 
 The exact structure of an aux item is specified elsewhere
 (@pxref{Auxiliary Information}).  The important fields here are the
@@ -785,6 +784,37 @@ parse the item anyway (in contrast to items in the misc-info list.)
 
 
 
+@node Aux-Item Inheritance
+@subsection Aux-Item Inheritance
+
+An aux item that is placed on a text can be inherited.  This means
+that if a comment or footnote to the text is created, an almost
+identical item will be created on the new text.  The @field{tag},
+@field{creator}, @field{flags} and @field{data} field will be
+inherited unchanged.  The @field{aux-no} might be given a different
+value.  A non-zero @field{inherit-limit} field will be decremented.
+The @field{created-at} timestamp will be set to the time when the new
+comment or footnote is created.
+
+Inheritance only happens at text creation time.  If a comment or
+footnote link is added later with @reqlink{add-comment} or
+@reqlink{add-footnote}, no items will be inherited.  Also, if the link
+is removed (via @reqlink{sub-comment} or @reqlink{sub-footnote}, the
+inherited items will still be in place.
+
+Inheritance only happens when the @field{inherit} bit is set, and if
+@field{inherit-limit} is 0 or greater than 1.  @xref{Auxiliary
+Information}, for more information.
+
+Inheritance has no meaning for items placed on the server or on a
+conference.
+
+It is possible for a predefined aux-item to behave in a way that isn't
+consistent with the description in this section.  The documentation
+for the specific aux-item should document any deviations.
+
+
+
 @node Predefined Aux-Item Types
 @subsection Predefined Aux-Item Types