--- a/doc/makefile-variables.txt	Thu Mar 19 14:35:58 2015 -0700
+++ b/doc/makefile-variables.txt	Thu Mar 19 20:44:31 2015 -0700
@@ -15,6 +15,8 @@
 * COMPONENT_ARCHIVE_URL is where the archive can be downloaded from.  This is
   typically constructed from $(COMPONENT_PROJECT_URL) and $(COMPONENT_ARCHIVE).
 * COMPONENT_BUGDB is the lower-case rendering of the BugDB cat/subcat.
+* REQUIRED_PACKAGES is a list of packages required to build or run the
+  component and its tests.
 
 These two are both initialized in make-rules/shared-macros.mk rather than any
 component-level Makefile, but are frequently referenced from the latter.