diff --git a/documentation/content/en/books/porters-handbook/uses/_index.adoc b/documentation/content/en/books/porters-handbook/uses/_index.adoc
--- a/documentation/content/en/books/porters-handbook/uses/_index.adoc
+++ b/documentation/content/en/books/porters-handbook/uses/_index.adoc
@@ -199,10 +199,14 @@
 
 The framework provides the following variables:
 
+`CABAL_REVISION`::
+Haskell packages hosted on Hackage may have revisions.
+Set this knob to an integer number to pull in revised package description.
+
 `USE_CABAL`::
 If the software uses Haskell dependencies, list them in this variable.
 Each item should be present on Hackage and be listed in form `packagename-_0.1.2_`.
-Dependencies can have revisions, which are specified after the `_` symbol.
+Dependencies can have revisions too, which are specified after the `_` symbol.
 Automatic generation of the dependency list is supported, see crossref:special[using-cabal,Building Haskell Applications with `cabal`].
 
 `CABAL_FLAGS`::