[1.8.x] Fixed #25710 -- Clarified the docs about what INTERNAL_IPS does.

Backport of 5abed864 from master

docs/ref/contrib/admin/admindocs.txt

@@ -137,6 +137,7 @@ Django's :ref:`template loaders <template-loaders>`. This can be a handy way to
 check if the specified template exists and to show where on the filesystem that
 template is stored.
 
+.. _admindocs-bookmarklets:
 
 Included Bookmarklets
 =====================

docs/ref/settings.txt

@@ -1656,9 +1656,12 @@ Default: ``()`` (Empty tuple)
 
 A tuple of IP addresses, as strings, that:
 
-* See debug comments, when :setting:`DEBUG` is ``True``
-* Receive X headers in admindocs if the ``XViewMiddleware`` is installed (see
-  :doc:`/ref/contrib/admin/admindocs`)
+* Allow the :func:`~django.template.context_processors.debug` context processor
+  to add some variables to the template context.
+* Can use the :ref:`admindocs bookmarklets <admindocs-bookmarklets>` even if
+  not logged in as a staff user.
+* Are marked as "internal" (as opposed to "EXTERNAL") in
+  :class:`~django.utils.log.AdminEmailHandler` emails.
 
 .. setting:: LANGUAGE_CODE
 

docs/ref/templates/api.txt

@@ -661,6 +661,8 @@ variables:
 django.template.context_processors.debug
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. function:: debug
+
 If this processor is enabled, every ``RequestContext`` will contain these two
 variables -- but only if your :setting:`DEBUG` setting is set to ``True`` and
 the request's IP address (``request.META['REMOTE_ADDR']``) is in the

docs/topics/logging.txt

@@ -555,7 +555,9 @@ Python logging module.
     message it receives.
 
     If the log record contains a ``request`` attribute, the full details
-    of the request will be included in the email.
+    of the request will be included in the email. The email subject will be
+    include the phrase "internal IP" if the client's IP address is in the
+    :setting:`INTERNAL_IPS` setting; if not, it will include "EXTERNAL IP".
 
     If the log record contains stack trace information, that stack
     trace will be included in the email.