Help: Document that CMP0097 is always NEW for FetchContent
Fixes: #25971
diff --git a/Help/policy/CMP0097.rst b/Help/policy/CMP0097.rst
index 66a7b96..d9141f5 100644
--- a/Help/policy/CMP0097.rst
+++ b/Help/policy/CMP0097.rst
@@ -4,9 +4,7 @@
.. versionadded:: 3.16
:command:`ExternalProject_Add` with ``GIT_SUBMODULES ""`` initializes no
-submodules. The policy also applies to :command:`FetchContent_Declare`,
-which uses the same download and update features as
-:command:`ExternalProject_Add`.
+submodules.
The commands provide a ``GIT_SUBMODULES`` option which controls what submodules
to initialize and update. Starting with CMake 3.16, explicitly setting
@@ -25,4 +23,15 @@
.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn
.. include:: STANDARD_ADVICE.txt
+.. note::
+
+ This policy also applies to :command:`FetchContent_Declare`,
+ which uses the same download and update features as
+ :command:`ExternalProject_Add`. However, due to an implementation deficiency
+ present since the policy was first introduced, CMake 3.16 and later always
+ uses the ``NEW`` behavior for :command:`FetchContent_Declare`, regardless of
+ the policy setting. Formally, this forcing of ``NEW`` behavior for
+ :command:`FetchContent_Declare` will continue to apply in future CMake
+ releases.
+
.. include:: DEPRECATED.txt
