add some simple notes about plaster in the narrative docs

docs/glossary.rst

@@ -366,6 +366,14 @@ Glossary
      :term:`WSGI` components together declaratively within an ``.ini``
      file.  It was developed by Ian Bicking.
 
+   plaster
+     `plaster <http://docs.pylonsproject.org/projects/plaster/en/latest/>` is
+     a library used by :app:`Pyramid` which acts as an abstraction between
+     command-line scripts and the file format used to load the :term:`WSGI`
+     components and application settings. By default :app:`Pyramid` ships
+     with the ``plaster_pastedeploy`` library installed which provides
+     integrated support for loading a :term:`PasteDeploy` INI file.
+
    Chameleon
      `chameleon <https://chameleon.readthedocs.org/en/latest/>`_ is an
      attribute language template compiler which supports the :term:`ZPT`

docs/narr/paste.rst

@@ -26,12 +26,7 @@ documentation, see http://pythonpaste.org/deploy/.
 PasteDeploy
 -----------
 
-:term:`PasteDeploy` is the system that Pyramid uses to allow :term:`deployment
-settings` to be specified using an ``.ini`` configuration file format.  It also
-allows the ``pserve`` command to work.  Its configuration format provides a
-convenient place to define application :term:`deployment settings` and WSGI
-server settings, and its server runner allows you to stop and start a Pyramid
-application easily.
+:term:`plaster` is the system that Pyramid uses to load settings from configuration files. The most common format for these files is an ``.ini`` format structured in a way defined by :term:`PasteDeploy`.  The format supports mechanisms to define WSGI app :term:`deployment settings`, WSGI server settings and logging. This allows the ``pserve`` command to work, allowing you to stop and start a Pyramid application easily.
 
 .. _pastedeploy_entry_points:
 
@@ -96,3 +91,8 @@ applications, servers, and :term:`middleware` defined within the configuration
 file.  The values in a ``[DEFAULT]`` section will be passed to your
 application's ``main`` function as ``global_config`` (see the reference to the
 ``main`` function in :ref:`init_py`).
+
+Alternative Configuration File Formats
+--------------------------------------
+
+It is possible to use different file formats with :app:`Pyramid` if you do not like :term:`PasteDeploy`. Under the hood all command-line scripts such as ``pserve`` and ``pshell`` pass the ``config_uri`` (e.g. ``development.ini``, ``production.ini``, etc) to the :term:`plaster` library which performs a lookup for an appropriate parser. For ``.ini`` files it uses PasteDeploy but you can register your own configuration formats that plaster will find instead.

docs/narr/startup.rst

@@ -38,7 +38,14 @@ Here's a high-level time-ordered overview of what happens when you press
    begin to run and serve an application using the information contained
    within the ``development.ini`` file.
 
-#. The framework finds a section named either ``[app:main]``,
+#. ``pserve`` passes the ``development.ini`` path to :term:`plaster` which
+   finds an available configuration loader that recognizes the ``ini`` format.
+
+#. :term:`plaster` finds the ``plaster_pastedeploy`` library which binds
+   the :term:`PasteDeploy` library and returns a parser that can understand
+   the format.
+
+#. The :term:`PasteDeploy` finds a section named either ``[app:main]``,
    ``[pipeline:main]``, or ``[composite:main]`` in the ``.ini`` file.  This
    section represents the configuration of a :term:`WSGI` application that will
    be served.  If you're using a simple application (e.g., ``[app:main]``), the