docs: add more pointers to configuration of embedded IPython

The "Running IPython from Python" section of the docs under "Configuring
IPython" gives a nice example of how to set IPython configuration
options when embedding IPython. Add more pointer to this part of the
documentation by linking to it from the docstrings of
IPython.{embed_kernel, start_ipython, start_kernel} and
IPython.terminal.embed.embed.

While at it, consistenly refer to the config argument as "a traitlets
:class:`Config` object".

Finally, also mention that options can be set with a 'Config' object in
the small paragraph under "IPython options".

IPython/__init__.py

@@ -1,156 +1,157 b''
 # PYTHON_ARGCOMPLETE_OK
 """
 IPython: tools for interactive and parallel computing in Python.
 
 https://ipython.org
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2008-2011, IPython Development Team.
 #  Copyright (c) 2001-2007, Fernando Perez <[e-mail]>
 #  Copyright (c) 2001, Janko Hauser <[e-mail]>
 #  Copyright (c) 2001, Nathaniel Gray <[e-mail]>
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import sys
 
 #-----------------------------------------------------------------------------
 # Setup everything
 #-----------------------------------------------------------------------------
 
 # Don't forget to also update setup.py when this changes!
 if sys.version_info < (3, 8):
     raise ImportError(
         """
 IPython 8+ supports Python 3.8 and above, following NEP 29.
 When using Python 2.7, please install IPython 5.x LTS Long Term Support version.
 Python 3.3 and 3.4 were supported up to IPython 6.x.
 Python 3.5 was supported with IPython 7.0 to 7.9.
 Python 3.6 was supported with IPython up to 7.16.
 Python 3.7 was still supported with the 7.x branch.
 
 See IPython `README.rst` file for more information:
 
     https://github.com/ipython/ipython/blob/main/README.rst
 
 """
     )
 
 #-----------------------------------------------------------------------------
 # Setup the top level names
 #-----------------------------------------------------------------------------
 
 from .core.getipython import get_ipython
 from .core import release
 from .core.application import Application
 from .terminal.embed import embed
 
 from .core.interactiveshell import InteractiveShell
 from .utils.sysinfo import sys_info
 from .utils.frame import extract_module_locals
 
 # Release data
 __author__ = '%s <%s>' % (release.author, release.author_email)
 __license__  = release.license
 __version__  = release.version
 version_info = release.version_info
 # list of CVEs that should have been patched in this release.
 # this is informational and should not be relied upon.
 __patched_cves__ = {"CVE-2022-21699", "CVE-2023-24816"}
 
 
 def embed_kernel(module=None, local_ns=None, **kwargs):
     """Embed and start an IPython kernel in a given scope.
 
     If you don't want the kernel to initialize the namespace
     from the scope of the surrounding function,
     and/or you want to load full IPython configuration,
     you probably want `IPython.start_kernel()` instead.
 
     Parameters
     ----------
     module : types.ModuleType, optional
         The module to load into IPython globals (default: caller)
     local_ns : dict, optional
         The namespace to load into IPython user namespace (default: caller)
     **kwargs : various, optional
         Further keyword args are relayed to the IPKernelApp constructor,
+        such as `config`, a traitlets :class:`Config` object (see :ref:`configure_start_ipython`),
         allowing configuration of the Kernel.  Will only have an effect
         on the first embed_kernel call for a given process.
     """
     
     (caller_module, caller_locals) = extract_module_locals(1)
     if module is None:
         module = caller_module
     if local_ns is None:
         local_ns = caller_locals
     
     # Only import .zmq when we really need it
     from ipykernel.embed import embed_kernel as real_embed_kernel
     real_embed_kernel(module=module, local_ns=local_ns, **kwargs)
 
 def start_ipython(argv=None, **kwargs):
     """Launch a normal IPython instance (as opposed to embedded)
 
     `IPython.embed()` puts a shell in a particular calling scope,
     such as a function or method for debugging purposes,
     which is often not desirable.
 
     `start_ipython()` does full, regular IPython initialization,
     including loading startup files, configuration, etc.
     much of which is skipped by `embed()`.
 
     This is a public API method, and will survive implementation changes.
 
     Parameters
     ----------
     argv : list or None, optional
         If unspecified or None, IPython will parse command-line options from sys.argv.
         To prevent any command-line parsing, pass an empty list: `argv=[]`.
     user_ns : dict, optional
         specify this dictionary to initialize the IPython user namespace with particular values.
     **kwargs : various, optional
         Any other kwargs will be passed to the Application constructor,
-        such as `config`.
+        such as `config`, a traitlets :class:`Config` object (see :ref:`configure_start_ipython`).
     """
     from IPython.terminal.ipapp import launch_new_instance
     return launch_new_instance(argv=argv, **kwargs)
 
 def start_kernel(argv=None, **kwargs):
     """Launch a normal IPython kernel instance (as opposed to embedded)
 
     `IPython.embed_kernel()` puts a shell in a particular calling scope,
     such as a function or method for debugging purposes,
     which is often not desirable.
 
     `start_kernel()` does full, regular IPython initialization,
     including loading startup files, configuration, etc.
     much of which is skipped by `embed_kernel()`.
 
     Parameters
     ----------
     argv : list or None, optional
         If unspecified or None, IPython will parse command-line options from sys.argv.
         To prevent any command-line parsing, pass an empty list: `argv=[]`.
     user_ns : dict, optional
         specify this dictionary to initialize the IPython user namespace with particular values.
     **kwargs : various, optional
         Any other kwargs will be passed to the Application constructor,
-        such as `config`.
+        such as `config`, a traitlets :class:`Config` object (see :ref:`configure_start_ipython`).
     """
     import warnings
 
     warnings.warn(
         "start_kernel is deprecated since IPython 8.0, use from `ipykernel.kernelapp.launch_new_instance`",
         DeprecationWarning,
         stacklevel=2,
     )
     from ipykernel.kernelapp import launch_new_instance
     return launch_new_instance(argv=argv, **kwargs)

IPython/terminal/embed.py

@@ -1,410 +1,410 b''
 # encoding: utf-8
 """
 An embedded IPython shell.
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 import sys
 import warnings
 
 from IPython.core import ultratb, compilerop
 from IPython.core import magic_arguments
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.core.interactiveshell import DummyMod, InteractiveShell
 from IPython.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.terminal.ipapp import load_default_config
 
 from traitlets import Bool, CBool, Unicode
 from IPython.utils.io import ask_yes_no
 
 from typing import Set
 
 class KillEmbedded(Exception):pass
 
 # kept for backward compatibility as IPython 6 was released with
 # the typo. See https://github.com/ipython/ipython/pull/10706
 KillEmbeded = KillEmbedded
 
 # This is an additional magic that is exposed in embedded shells.
 @magics_class
 class EmbeddedMagics(Magics):
 
     @line_magic
     @magic_arguments.magic_arguments()
     @magic_arguments.argument('-i', '--instance', action='store_true',
                               help='Kill instance instead of call location')
     @magic_arguments.argument('-x', '--exit', action='store_true',
                               help='Also exit the current session')
     @magic_arguments.argument('-y', '--yes', action='store_true',
                               help='Do not ask confirmation')
     def kill_embedded(self, parameter_s=''):
         """%kill_embedded : deactivate for good the current embedded IPython
 
         This function (after asking for confirmation) sets an internal flag so
         that an embedded IPython will never activate again for the given call
         location. This is useful to permanently disable a shell that is being
         called inside a loop: once you've figured out what you needed from it,
         you may then kill it and the program will then continue to run without
         the interactive shell interfering again.
 
         Kill Instance Option:
 
             If for some reasons you need to kill the location where the instance
             is created and not called, for example if you create a single
             instance in one place and debug in many locations, you can use the
             ``--instance`` option to kill this specific instance. Like for the
             ``call location`` killing an "instance" should work even if it is
             recreated within a loop.
 
         .. note::
 
             This was the default behavior before IPython 5.2
 
         """
 
         args = magic_arguments.parse_argstring(self.kill_embedded, parameter_s)
         print(args)
         if args.instance:
             # let no ask
             if not args.yes:
                 kill = ask_yes_no(
                     "Are you sure you want to kill this embedded instance? [y/N] ", 'n')
             else:
                 kill = True
             if kill:
                 self.shell._disable_init_location()
                 print("This embedded IPython instance will not reactivate anymore "
                       "once you exit.")
         else:
             if not args.yes:
                 kill = ask_yes_no(
                     "Are you sure you want to kill this embedded call_location? [y/N] ", 'n')
             else:
                 kill = True
             if kill:
                 self.shell.embedded_active = False
                 print("This embedded IPython  call location will not reactivate anymore "
                       "once you exit.")
 
         if args.exit:
             # Ask-exit does not really ask, it just set internals flags to exit
             # on next loop.
             self.shell.ask_exit()
 
 
     @line_magic
     def exit_raise(self, parameter_s=''):
         """%exit_raise Make the current embedded kernel exit and raise and exception.
 
         This function sets an internal flag so that an embedded IPython will
         raise a `IPython.terminal.embed.KillEmbedded` Exception on exit, and then exit the current I. This is
         useful to permanently exit a loop that create IPython embed instance.
         """
 
         self.shell.should_raise = True
         self.shell.ask_exit()
 
 
 class _Sentinel:
     def __init__(self, repr):
         assert isinstance(repr, str)
         self.repr = repr
 
     def __repr__(self):
         return repr
 
 
 class InteractiveShellEmbed(TerminalInteractiveShell):
 
     dummy_mode = Bool(False)
     exit_msg = Unicode('')
     embedded = CBool(True)
     should_raise = CBool(False)
     # Like the base class display_banner is not configurable, but here it
     # is True by default.
     display_banner = CBool(True)
     exit_msg = Unicode()
 
     # When embedding, by default we don't change the terminal title
     term_title = Bool(False,
         help="Automatically set the terminal title"
     ).tag(config=True)
 
     _inactive_locations: Set[str] = set()
 
     def _disable_init_location(self):
         """Disable the current Instance creation location"""
         InteractiveShellEmbed._inactive_locations.add(self._init_location_id)
 
     @property
     def embedded_active(self):
         return (self._call_location_id not in InteractiveShellEmbed._inactive_locations)\
             and (self._init_location_id not in InteractiveShellEmbed._inactive_locations)
 
     @embedded_active.setter
     def embedded_active(self, value):
         if value:
             InteractiveShellEmbed._inactive_locations.discard(
                 self._call_location_id)
             InteractiveShellEmbed._inactive_locations.discard(
                 self._init_location_id)
         else:
             InteractiveShellEmbed._inactive_locations.add(
                 self._call_location_id)
 
     def __init__(self, **kw):
         assert (
             "user_global_ns" not in kw
         ), "Key word argument `user_global_ns` has been replaced by `user_module` since IPython 4.0."
 
         clid = kw.pop('_init_location_id', None)
         if not clid:
             frame = sys._getframe(1)
             clid = '%s:%s' % (frame.f_code.co_filename, frame.f_lineno)
         self._init_location_id = clid
 
         super(InteractiveShellEmbed,self).__init__(**kw)
 
         # don't use the ipython crash handler so that user exceptions aren't
         # trapped
         sys.excepthook = ultratb.FormattedTB(color_scheme=self.colors,
                                              mode=self.xmode,
                                              call_pdb=self.pdb)
 
     def init_sys_modules(self):
         """
         Explicitly overwrite :mod:`IPython.core.interactiveshell` to do nothing.
         """
         pass
 
     def init_magics(self):
         super(InteractiveShellEmbed, self).init_magics()
         self.register_magics(EmbeddedMagics)
 
     def __call__(
         self,
         header="",
         local_ns=None,
         module=None,
         dummy=None,
         stack_depth=1,
         compile_flags=None,
         **kw
     ):
         """Activate the interactive interpreter.
 
         __call__(self,header='',local_ns=None,module=None,dummy=None) -> Start
         the interpreter shell with the given local and global namespaces, and
         optionally print a header string at startup.
 
         The shell can be globally activated/deactivated using the
         dummy_mode attribute. This allows you to turn off a shell used
         for debugging globally.
 
         However, *each* time you call the shell you can override the current
         state of dummy_mode with the optional keyword parameter 'dummy'. For
         example, if you set dummy mode on with IPShell.dummy_mode = True, you
         can still have a specific call work by making it as IPShell(dummy=False).
         """
 
         # we are called, set the underlying interactiveshell not to exit.
         self.keep_running = True
 
         # If the user has turned it off, go away
         clid = kw.pop('_call_location_id', None)
         if not clid:
             frame = sys._getframe(1)
             clid = '%s:%s' % (frame.f_code.co_filename, frame.f_lineno)
         self._call_location_id = clid
 
         if not self.embedded_active:
             return
 
         # Normal exits from interactive mode set this flag, so the shell can't
         # re-enter (it checks this variable at the start of interactive mode).
         self.exit_now = False
 
         # Allow the dummy parameter to override the global __dummy_mode
         if dummy or (dummy != 0 and self.dummy_mode):
             return
 
         # self.banner is auto computed
         if header:
             self.old_banner2 = self.banner2
             self.banner2 = self.banner2 + '\n' + header + '\n'
         else:
             self.old_banner2 = ''
 
         if self.display_banner:
             self.show_banner()
 
         # Call the embedding code with a stack depth of 1 so it can skip over
         # our call and get the original caller's namespaces.
         self.mainloop(
             local_ns, module, stack_depth=stack_depth, compile_flags=compile_flags
         )
 
         self.banner2 = self.old_banner2
 
         if self.exit_msg is not None:
             print(self.exit_msg)
 
         if self.should_raise:
             raise KillEmbedded('Embedded IPython raising error, as user requested.')
 
     def mainloop(
         self,
         local_ns=None,
         module=None,
         stack_depth=0,
         compile_flags=None,
     ):
         """Embeds IPython into a running python program.
 
         Parameters
         ----------
         local_ns, module
             Working local namespace (a dict) and module (a module or similar
             object). If given as None, they are automatically taken from the scope
             where the shell was called, so that program variables become visible.
         stack_depth : int
             How many levels in the stack to go to looking for namespaces (when
             local_ns or module is None). This allows an intermediate caller to
             make sure that this function gets the namespace from the intended
             level in the stack. By default (0) it will get its locals and globals
             from the immediate caller.
         compile_flags
             A bit field identifying the __future__ features
             that are enabled, as passed to the builtin :func:`compile` function.
             If given as None, they are automatically taken from the scope where
             the shell was called.
 
         """
         
         # Get locals and globals from caller
         if ((local_ns is None or module is None or compile_flags is None)
             and self.default_user_namespaces):
             call_frame = sys._getframe(stack_depth).f_back
 
             if local_ns is None:
                 local_ns = call_frame.f_locals
             if module is None:
                 global_ns = call_frame.f_globals
                 try:
                     module = sys.modules[global_ns['__name__']]
                 except KeyError:
                     warnings.warn("Failed to get module %s" % \
                         global_ns.get('__name__', 'unknown module')
                     )
                     module = DummyMod()
                     module.__dict__ = global_ns
             if compile_flags is None:
                 compile_flags = (call_frame.f_code.co_flags &
                                  compilerop.PyCF_MASK)
         
         # Save original namespace and module so we can restore them after 
         # embedding; otherwise the shell doesn't shut down correctly.
         orig_user_module = self.user_module
         orig_user_ns = self.user_ns
         orig_compile_flags = self.compile.flags
         
         # Update namespaces and fire up interpreter
         
         # The global one is easy, we can just throw it in
         if module is not None:
             self.user_module = module
 
         # But the user/local one is tricky: ipython needs it to store internal
         # data, but we also need the locals. We'll throw our hidden variables
         # like _ih and get_ipython() into the local namespace, but delete them
         # later.
         if local_ns is not None:
             reentrant_local_ns = {k: v for (k, v) in local_ns.items() if k not in self.user_ns_hidden.keys()}
             self.user_ns = reentrant_local_ns
             self.init_user_ns()
 
         # Compiler flags
         if compile_flags is not None:
             self.compile.flags = compile_flags
 
         # make sure the tab-completer has the correct frame information, so it
         # actually completes using the frame's locals/globals
         self.set_completer_frame()
 
         with self.builtin_trap, self.display_trap:
             self.interact()
         
         # now, purge out the local namespace of IPython's hidden variables.
         if local_ns is not None:
             local_ns.update({k: v for (k, v) in self.user_ns.items() if k not in self.user_ns_hidden.keys()})
 
         
         # Restore original namespace so shell can shut down when we exit.
         self.user_module = orig_user_module
         self.user_ns = orig_user_ns
         self.compile.flags = orig_compile_flags
 
 
 def embed(*, header="", compile_flags=None, **kwargs):
     """Call this to embed IPython at the current point in your program.
 
     The first invocation of this will create an :class:`InteractiveShellEmbed`
     instance and then call it.  Consecutive calls just call the already
     created instance.
 
     If you don't want the kernel to initialize the namespace
     from the scope of the surrounding function,
     and/or you want to load full IPython configuration,
     you probably want `IPython.start_ipython()` instead.
 
     Here is a simple example::
 
         from IPython import embed
         a = 10
         b = 20
         embed(header='First time')
         c = 30
         d = 40
         embed()
 
-    Full customization can be done by passing a :class:`Config` in as the
-    config argument.
+    Full customization can be done by passing a traitlets :class:`Config` in as the
+    `config` argument (see :ref:`configure_start_ipython`).
     """
     config = kwargs.get('config')
     if config is None:
         config = load_default_config()
         config.InteractiveShellEmbed = config.TerminalInteractiveShell
         kwargs['config'] = config
     using = kwargs.get('using', 'sync')
     if using :
         kwargs['config'].update({'TerminalInteractiveShell':{'loop_runner':using, 'colors':'NoColor', 'autoawait': using!='sync'}})
     #save ps1/ps2 if defined
     ps1 = None
     ps2 = None
     try:
         ps1 = sys.ps1
         ps2 = sys.ps2
     except AttributeError:
         pass
     #save previous instance
     saved_shell_instance = InteractiveShell._instance
     if saved_shell_instance is not None:
         cls = type(saved_shell_instance)
         cls.clear_instance()
     frame = sys._getframe(1)
     shell = InteractiveShellEmbed.instance(_init_location_id='%s:%s' % (
         frame.f_code.co_filename, frame.f_lineno), **kwargs)
     shell(header=header, stack_depth=2, compile_flags=compile_flags,
         _call_location_id='%s:%s' % (frame.f_code.co_filename, frame.f_lineno))
     InteractiveShellEmbed.clear_instance()
     #restore previous instance
     if saved_shell_instance is not None:
         cls = type(saved_shell_instance)
         cls.clear_instance()
         for subclass in cls._walk_mro():
             subclass._instance = saved_shell_instance
     if ps1 is not None:
         sys.ps1 = ps1
         sys.ps2 = ps2

docs/source/config/intro.rst

@@ -1,235 +1,235 b''
 =====================================
 Introduction to IPython configuration
 =====================================
 
 .. _setting_config:
 
 Setting configurable options
 ============================
 
 Many of IPython's classes have configurable attributes (see
 :doc:`options/index` for the list). These can be
 configured in several ways.
 
 Python configuration files
 --------------------------
 
 To create the blank configuration files, run::
 
     ipython profile create [profilename]
 
 If you leave out the profile name, the files will be created for the
 ``default`` profile (see :ref:`profiles`). These will typically be located in
 :file:`~/.ipython/profile_default/`, and will be named
 :file:`ipython_config.py`, for historical reasons you may also find files
 named with IPython prefix instead of Jupyter:
 :file:`ipython_notebook_config.py`, etc. The settings in
 :file:`ipython_config.py` apply to all IPython commands.
 
 By default, configuration files are fully featured Python scripts that can
 execute arbitrary code, the main usage is to set value on the configuration
 object ``c`` which exist in your configuration file.
 
 You can then configure class attributes like this::
 
     c.InteractiveShell.automagic = False
 
 Be careful with spelling--incorrect names will simply be ignored, with
 no error. 
 
 To add to a collection which may have already been defined elsewhere or have
 default values, you can use methods like those found on lists, dicts and
 sets: append, extend, :meth:`~traitlets.config.LazyConfigValue.prepend` (like
 extend, but at the front), add and update (which works both for dicts and
 sets)::
 
     c.InteractiveShellApp.extensions.append('Cython')
 
 .. versionadded:: 2.0
    list, dict and set methods for config values
 
 Example configuration file
 ``````````````````````````
 
 ::
 
     # sample ipython_config.py
 
     c.TerminalIPythonApp.display_banner = True
     c.InteractiveShellApp.log_level = 20
     c.InteractiveShellApp.extensions = [
         'myextension'
     ]
     c.InteractiveShellApp.exec_lines = [
         'import numpy',
         'import scipy'
     ]
     c.InteractiveShellApp.exec_files = [
         'mycode.py',
         'fancy.ipy'
     ]
     c.InteractiveShell.colors = 'LightBG'
     c.InteractiveShell.xmode = 'Context'
     c.TerminalInteractiveShell.confirm_exit = False
     c.TerminalInteractiveShell.editor = 'nano'
 
     c.PrefilterManager.multi_line_specials = True
 
     c.AliasManager.user_aliases = [
      ('la', 'ls -al')
     ]
 
 JSON Configuration files
 ------------------------
 
 In case where executability of configuration can be problematic, or
 configurations need to be modified programmatically, IPython also support a
 limited set of functionalities via ``.json`` configuration files. 
 
 You can defined most of the configuration options via a json object which
 hierarchy represent the value you would normally set on the ``c`` object of
 ``.py`` configuration files. The following ``ipython_config.json`` file::
 
     {
         "InteractiveShell": {
             "colors": "LightBG",
         },
         "InteractiveShellApp": {
             "extensions": [
                 "myextension"
             ]
         },
         "TerminalInteractiveShell": {
             "editor": "nano"
         }
     }
 
 Is equivalent to the following ``ipython_config.py``::
 
     c.InteractiveShellApp.extensions = [
         'myextension'
     ]
 
     c.InteractiveShell.colors = 'LightBG'
     c.TerminalInteractiveShell.editor = 'nano'
 
 
 Command line arguments
 ----------------------
 
 Every configurable value can be set from the command line, using this
 syntax::
 
     ipython --ClassName.attribute=value
 
 Many frequently used options have short aliases and flags, such as
 ``--matplotlib`` (to integrate with a matplotlib GUI event loop) or
 ``--pdb`` (automatic post-mortem debugging of exceptions).
 
 To see all of these abbreviated options, run::
 
     ipython --help
     jupyter notebook --help
     # etc.
 
 Options specified at the command line, in either format, override
 options set in a configuration file.
 
 The config magic
 ----------------
 
 You can also modify config from inside IPython, using a magic command::
 
     %config IPCompleter.greedy = True
 
 At present, this only affects the current session - changes you make to
 config are not saved anywhere. Also, some options are only read when
 IPython starts, so they can't be changed like this.
 
 .. _configure_start_ipython:
 
 Running IPython from Python
 ----------------------------
 
 If you are using :ref:`embedding` to start IPython from a normal 
 python file, you can set configuration options the same way as in a 
-config file by creating a traitlets config object and passing it to 
+config file by creating a traitlets :class:`Config` object and passing it to 
 start_ipython like in the example below.
 
 .. literalinclude:: ../../../examples/Embedding/start_ipython_config.py
     :language: python
 
 .. _profiles:
 
 Profiles
 ========
 
 IPython can use multiple profiles, with separate configuration and
 history. By default, if you don't specify a profile, IPython always runs
 in the ``default`` profile. To use a new profile::
 
     ipython profile create foo   # create the profile foo
     ipython --profile=foo        # start IPython using the new profile
 
 Profiles are typically stored in :ref:`ipythondir`, but you can also keep
 a profile in the current working directory, for example to distribute it
 with a project. To find a profile directory on the filesystem::
 
     ipython locate profile foo
 
 .. _ipythondir:
 
 The IPython directory
 =====================
 
 IPython stores its files---config, command history and extensions---in
 the directory :file:`~/.ipython/` by default.
 
 .. envvar:: IPYTHONDIR
 
    If set, this environment variable should be the path to a directory,
    which IPython will use for user data. IPython will create it if it
    does not exist.
 
 .. option:: --ipython-dir=<path>
 
    This command line option can also be used to override the default
    IPython directory.
 
 To see where IPython is looking for the IPython directory, use the command
 ``ipython locate``, or the Python function :func:`IPython.paths.get_ipython_dir`.
 
 
 Systemwide configuration
 ========================
 
 It can be useful to deploy systemwide ipython or ipykernel configuration
 when managing environment for many users. At startup time IPython and
 IPykernel will search for configuration file in multiple systemwide
 locations, mainly:
 
   - ``/etc/ipython/``
   - ``/usr/local/etc/ipython/``
 
 When the global install is a standalone python distribution it may also
 search in distribution specific location, for example:
 
   - ``$ANACONDA_LOCATION/etc/ipython/``
 
 In those locations, Terminal IPython will look for a file called
 ``ipython_config.py`` and ``ipython_config.json``, ipykernel will look for
 ``ipython_kernel_config.py`` and ``ipython_kernel.json``.
 
 Configuration files are loaded in order and merged with configuration on
 later location taking precedence on earlier locations (that is to say a user
 can overwrite a systemwide configuration option).
 
 You can see all locations in which IPython is looking for configuration files
 by starting ipython in debug mode::
 
     $ ipython --debug -c 'exit()'
 
 Identically with ipykernel though the command is currently blocking until
 this process is killed with ``Ctrl-\``::
  
     $ python -m ipykernel --debug

docs/source/config/options/index.rst

@@ -1,12 +1,12 b''
 ===============
 IPython options
 ===============
 
 Any of the options listed here can be set in config files, at the
-command line, or from inside IPython. See :ref:`setting_config` for
-details.
+command line, from inside IPython, or using a traitlets :class:`Config` object.
+See :ref:`setting_config` for details.
 
 .. toctree::
 
    terminal
    kernel