diff --git a/releng.control/commonVariations.shsource b/releng.control/commonVariations.shsource
index 94843acc4abe6275d749bb6ae3e50c59591d9ce7..4373c705f650bd8aec928bf65e2ded7086017542 100644
--- a/releng.control/commonVariations.shsource
+++ b/releng.control/commonVariations.shsource
@@ -9,6 +9,11 @@
 # be included in other sh files, with "source" command, not 
 # executed on its own. 
 
+# Some things _have_ to go in this file, instead of being an ant property, 
+# since they may be used outside the contect of ant (or, before ant get's started). 
+# as one example, anything used directly in the cc_config.xml file has to be 
+# provided as environment variable, since it can not import ant property files 
+# like most ant project files can.
 
 export BUILD_HOME=/shared/webtools
 
@@ -55,11 +60,14 @@ export USE_QUIET=false
 # setting to true will result in TONS of ouput
 export USE_DEBUG=false
 
-# should be true for production, false for local
+# should be true for production, false for local. 
+# it can be set to true for local builds, but then the 
+# properties in upload.properties need to be set to valid values.
 export BUILD_UPLOAD=true
 
 # if true, locally existing maps will be used as is, instead of being 
-# checked out afresh.
+# checked out afresh. Set to false for production builds, so maps are 
+# always fresh.
 export USE_LOCAL_MAPS=false
 
 # normally, cvs logging output can be "really quiet", but if problems, then it can be turned back on