diff --git a/doc/lispref/buffers.texi b/doc/lispref/buffers.texi
index 5375eb64155..5aa712e4247 100644
--- a/doc/lispref/buffers.texi
+++ b/doc/lispref/buffers.texi
@@ -1000,6 +1000,12 @@ Satisfied if the buffer's major mode is equal to @var{expr}.  Prefer
 using @code{derived-mode} instead, when both can work.  Note that this
 condition might fail to report a match if @code{buffer-match-p} is
 invoked before the major mode of the buffer has been established.
+@item category
+This is pertinent only when this function is called by
+@code{display-buffer} (@pxref{Buffer Display Action Alists}), and is
+satisfied if the action alist with which @code{display-buffer} was
+called includes @w{@code{(category . @var{expr})}} in the value of its
+@var{action} argument.  @xref{Buffer Display Action Alists}.
 @end table
 @item t
 Satisfied by any buffer.  A convenient alternative to @code{""} (empty
diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index f5963d984e9..c7e575b0e4f 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -2656,6 +2656,9 @@ for example:
 @end group
 @end example
 
+@noindent
+@xref{Buffer List, @code{buffer-match-p}}.
+
 Regardless of the displayed buffer's name the caller defines a category
 as a symbol @code{comint}.  Then @code{display-buffer-alist} matches
 this category for all buffers displayed with the same category.
@@ -3405,9 +3408,13 @@ windows were selected afterwards within this command.
 @vindex category@r{, a buffer display action alist entry}
 @item category
 If the caller of @code{display-buffer} passes an alist entry
-@code{(category . symbol)} in its @var{action} argument, then you can
-match the displayed buffer by using the same category in the condition
-part of @code{display-buffer-alist} entries.
+@w{@code{(category . @var{symbol})}} in its @var{action} argument, then you
+can match the displayed buffer by using the same category symbol in the
+condition part of @code{display-buffer-alist} entries.  @xref{Buffer
+List, @code{buffer-match-p}}.  Thus, if a Lisp program uses a particular
+@var{symbol} as the category when calling @code{display-buffer}, users
+can customize how these buffers will be displayed by including such an
+entry in @code{display-buffer-alist}.
 @end table
 
 By convention, the entries @code{window-height}, @code{window-width}
diff --git a/lisp/subr.el b/lisp/subr.el
index 2152f16ba95..e9d12644d0e 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -7447,9 +7447,10 @@ CONDITION is either:
   * `major-mode': the buffer matches if the buffer's major mode
     is eq to the cons-cell's cdr.  Prefer using `derived-mode'
     instead when both can work.
-  * `category': the buffer matches a category as a symbol if
-    the caller of `display-buffer' provides `(category . symbol)'
-    in its action argument.
+  * `category': when this function is called from `display-buffer',
+    the buffer matches if the caller of `display-buffer' provides
+    `(category . SYMBOL)' in its ACTION argument, and SYMBOL is `eq'
+    to the cons-cell's cdr.
   * `not': the cadr is interpreted as a negation of a condition.
   * `and': the cdr is a list of recursive conditions, that all have
     to be met.