[PATCH] docs: add CONVERSION_CMD definition

[Aatir Manzur <aatrapps@gmail.com>]

Signed-off-by Aatir Manzur <aatrapps@gmail.com>
---
 documentation/migration-guides/migration-2.2.rst | 2 +-
 documentation/migration-guides/migration-2.4.rst | 2 +-
 documentation/migration-guides/migration-3.4.rst | 2 +-
 documentation/ref-manual/variables.rst           | 9 +++++++++
 4 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/documentation/migration-guides/migration-2.2.rst b/documentation/migration-guides/migration-2.2.rst
index fe7bc2cf5..16e48cc87 100644
--- a/documentation/migration-guides/migration-2.2.rst
+++ b/documentation/migration-guides/migration-2.2.rst
@@ -442,7 +442,7 @@ The following miscellaneous changes have occurred:
 -  :ref:`ref-classes-image`: Renamed COMPRESS(ION) to CONVERSION. This change
    means that ``COMPRESSIONTYPES``, ``COMPRESS_DEPENDS`` and
    ``COMPRESS_CMD`` are deprecated in favor of ``CONVERSIONTYPES``,
-   ``CONVERSION_DEPENDS`` and ``CONVERSION_CMD``. The ``COMPRESS*``
+   ``CONVERSION_DEPENDS`` and :term:`CONVERSION_CMD`. The ``COMPRESS*``
    variable names will still work in the 2.2 release but metadata that
    does not need to be backwards-compatible should be changed to use the
    new names as the ``COMPRESS*`` ones will be removed in a future
diff --git a/documentation/migration-guides/migration-2.4.rst b/documentation/migration-guides/migration-2.4.rst
index ef5f32e6e..964ed9293 100644
--- a/documentation/migration-guides/migration-2.4.rst
+++ b/documentation/migration-guides/migration-2.4.rst
@@ -301,7 +301,7 @@ The following are additional changes:
    likely be removed in the next Yocto Project release.
 
 -  The ``vmdk``, ``vdi``, and ``qcow2`` image file types are now used in
-   conjunction with the "wic" image type through ``CONVERSION_CMD``.
+   conjunction with the "wic" image type through :term:`CONVERSION_CMD`.
    Consequently, the equivalent image types are now ``wic.vmdk``,
    ``wic.vdi``, and ``wic.qcow2``, respectively.
 
diff --git a/documentation/migration-guides/migration-3.4.rst b/documentation/migration-guides/migration-3.4.rst
index 8db43a145..c600129ec 100644
--- a/documentation/migration-guides/migration-3.4.rst
+++ b/documentation/migration-guides/migration-3.4.rst
@@ -252,7 +252,7 @@ Miscellaneous
 
 - The previously deprecated ``COMPRESS_CMD`` and
   ``CVE_CHECK_CVE_WHITELIST`` variables have been removed. Use
-  ``CONVERSION_CMD`` and ``CVE_CHECK_WHITELIST`` (replaced by
+  :term:`CONVERSION_CMD` and ``CVE_CHECK_WHITELIST`` (replaced by
   :term:`CVE_CHECK_IGNORE` in version 3.5) respectively
   instead.
 
diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 8f7b01c12..bc59b574d 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -1297,6 +1297,15 @@ system and gives an overview of their function and contents.
       the recipe will be skipped, and if the build system attempts to build
       the recipe then an error will be triggered.
 
+   :term:`CONVERSION_CMD`
+      This variable is used for storing image conversion commands. 
+      Image conversion can convert an image into different objects like:
+      - compressed version of the image
+      - checksums for the image
+      An exmple of :term:`CONVERSION_CMD` 
+      from :ref:`image-types <ref-classes-image_types>` class is:
+      CONVERSION_CMD:lzo = "lzop -9 ${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.${type}"
+
    :term:`COPY_LIC_DIRS`
       If set to "1" along with the
       :term:`COPY_LIC_MANIFEST` variable, the
-- 
2.31.0