diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 6c3f62d9f..653bdb1b4 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -9396,6 +9396,17 @@ system and gives an overview of their function and contents.
 
       See also :term:`SPDX_INCLUDE_SOURCES`.
 
+   :term:`SPDX_GIT_PURL_MAPPINGS`
+      A space separated list of ``domain:purl_type`` mappings to configure PURL
+      (Package URLs) generation for Git source downloads.
+
+      For example, adding ``gitlab.example.com:pkg:gitlab`` to this variable
+      will map repositories hosted on "gitlab.example.com" to the ``pkg:gitlab``
+      PURL type.
+
+      See also the :term:`SPDX_PACKAGE_URLS` variable for more information on
+      PURLs.
+
    :term:`SPDX_IMAGE_SUPPLIER`
       The name of an agent variable prefix describing the organization or
       person who supplies the image SBOM. When set, the supplier is attached