diff --git a/picom.sample.conf b/picom.sample.conf
index 398d395..89f8d69 100644
--- a/picom.sample.conf
+++ b/picom.sample.conf
@@ -14,6 +14,7 @@ size-transition = true
 #################################
 #             Corners           #
 #################################
+# requires: https://github.com/sdhand/compton or https://github.com/jonaburg/picom
 corner-radius = 25.0;
 rounded-corners-exclude = [
   #"window_type = 'normal'",