diff --git a/doc/hardware/porting/board_porting.rst b/doc/hardware/porting/board_porting.rst
index 403c54a382d..5b21cbf2b68 100644
--- a/doc/hardware/porting/board_porting.rst
+++ b/doc/hardware/porting/board_porting.rst
@@ -783,21 +783,31 @@ There are some extra things you'll need to do:
 Board extensions
 ****************
 
-Board extensions are designed for downstream users, for example,
+Boards already supported by Zephyr can be extended by downstream users, such as
 ``example-application`` or vendor SDKs. In some situations, certain hardware
-description or `choices <devicetree-chosen-nodes>`_ can not be added in the
+description or :ref:`choices <devicetree-chosen-nodes>` can not be added in the
 upstream Zephyr repository, but they can be in a downstream project, where
 custom bindings or driver classes can also be created. This feature may also be
 useful in development phases, when the board skeleton lives upstream, but other
 features are developed in a downstream module.
 
-Board extensions are board fragments that can be present in a board root
-folder, under ``${BOARD_ROOT}/boards/extensions``. The extension folder must
-follow the naming structure of the original board to extend. The board extension
-directory may contain Kconfig fragments and/or devicetree overlays. Board
-extensions are, by default, automatically loaded and applied on top of board
+Board extensions are board fragments that can be present in an out-of-tree board
+root folder, under ``${BOARD_ROOT}/boards/extensions``. Here is an example
+structure of an extension for the ``plank`` board and its revisions:
+
+.. code-block:: none
+
+   boards/extensions/plank
+   ├── plank.conf                # optional
+   ├── plank_<revision>.conf     # optional
+   ├── plank.overlay             # optional
+   └── plank_<revision>.overlay  # optional
+
+A board extension directory must follow the naming structure of the original
+board it extends. It may contain Kconfig fragments and/or devicetree overlays.
+Extensions are, by default, automatically loaded and applied on top of board
 files, before anything else. There is no guarantee on which order extensions are
-applied, in case multiple exist. This feature shall be disabled by passing
+applied, in case multiple exist. This feature can be disabled by passing
 ``-DBOARD_EXTENSIONS=OFF`` when building.
 
 Note that board extensions need to follow the