--- a/doc/makefile-variables.txt	Mon Feb 16 13:54:04 2015 -0800
+++ b/doc/makefile-variables.txt	Sun Feb 15 19:02:09 2015 -0600
@@ -32,6 +32,8 @@
 	done
   before you 'hg commit' your merge.
 * 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.