diff --git a/Makefile b/Makefile
index 074674a..5a83251 100644
--- a/Makefile
+++ b/Makefile
@@ -91,6 +91,8 @@ EXTRAMAKEARGS = O=$(O)
 NEED_WRAPPER=y
 endif
 
+BUILDROOT_CONFIG=$(CONFIG_DIR)/.config
+
 # Pull in the user's configuration file
 ifeq ($(filter $(noconfig_targets),$(MAKECMDGOALS)),)
 -include $(CONFIG_DIR)/.config
@@ -282,6 +284,15 @@ HOSTCC  := $(CCACHE) $(HOSTCC)
 HOSTCXX := $(CCACHE) $(HOSTCXX)
 endif
 
+# Scripts in support/ or post-build scripts may need to reference
+# these locations, so export them so it is easier to use
+export BUILDROOT_CONFIG
+export TARGET_DIR
+export STAGING_DIR
+export HOST_DIR
+export BINARIES_DIR
+export BASE_DIR O   # O and BASE_DIR are the same
+
 #############################################################
 #
 # You should probably leave this stuff alone unless you know
diff --git a/docs/manual/customize-rootfs.txt b/docs/manual/customize-rootfs.txt
index a1a556b..fe3ea7e 100644
--- a/docs/manual/customize-rootfs.txt
+++ b/docs/manual/customize-rootfs.txt
@@ -37,6 +37,13 @@ there are a few ways to customize the resulting target filesystem.
   certain package generates wrong or unneeded files, you should fix
   that package rather than work around it with a post-build cleanup
   script. _Among these first 3 methods, this one should be preferred_.
+  You may also use these variables in your post-build script:
+    - +BUILDROOT_CONFIG+: the path to the Buildroot .config file
+    - +HOST_DIR+, +STAGING_DIR+, +TARGET_DIR+: see
+      xref:generic-package-reference[]
+    - +BINARIES_DIR+: the place were all binary files (aka images) are
+      stored
+    - +BASE_DIR+ (or +O+): the base output directory
 
 * A special package, 'customize', stored in +package/customize+ can be
   used. You can put all the files that you want to see in the final