Rewording

Author: Nyholm

reference/configuration/kernel.rst

@@ -84,19 +84,6 @@ method to return the right project directory::
         }
     }
 
-Build Directory
-~~~~~~~~~~~~~~~
-
-**type**: ``string`` **default**: ``$this->getCacheDir()``
-
-This returns the absolute path of a build directory of your Symfony project. This
-directory can be warmed up before deployment and be used as a read-only filesystem
-(ie Docker or AWS Lambda).
-
-This value is exposed via the ``kernel.build_dir`` configuration parameter and
-the :method:`Symfony\\Component\\HttpKernel\\Kernel::getBuildDir` method. To
-change this setting, override the ``getBuildDir()`` method to return the correct
-build directory.
 
 Cache Directory
 ~~~~~~~~~~~~~~~
@@ -113,6 +100,27 @@ the :method:`Symfony\\Component\\HttpKernel\\Kernel::getCacheDir` method. To
 change this setting, override the ``getCacheDir()`` method to return the correct
 cache directory.
 
+Build Directory
+~~~~~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``$this->getCacheDir()``
+
+.. versionadded:: 5.2
+
+    The build directory feature was introduced in Symfony 5.2.
+
+This returns the absolute path of a build directory of your Symfony project. This
+directory can be used to separate read-only cache (i.e. the compiled container)
+from read-write cache (i.e. cache pools). Specify a non-default value when the
+application is deployed in a read-only filesystem like a Docker container or AWS
+Lambda.
+
+This value is exposed via the ``kernel.build_dir`` configuration parameter and
+the :method:`Symfony\\Component\\HttpKernel\\Kernel::getBuildDir` method. To
+change this setting, override the ``getBuildDir()`` method to return the correct
+build directory.
+
+
 Log Directory
 ~~~~~~~~~~~~~