diff --git a/R/defaults/main.yml b/R/defaults/main.yml
index c3215d4b..67620acb 100644
--- a/R/defaults/main.yml
+++ b/R/defaults/main.yml
@@ -1,5 +1,7 @@
 ---
 #
+# There's an untrusted Ubuntu PPA repository with gobs of packages and dependencies: https://launchpad.net/~marutter/+archive/ubuntu/c2d4u NOT TESTED
+#
 # To list the installed R packages
 # Run R, then execute
 # packinfo <- installed.packages (fields = c ("Package", "Version"))