diff --git a/vars/default_vars.yml b/vars/default_vars.yml
index b223ed73e..9b428571b 100644
--- a/vars/default_vars.yml
+++ b/vars/default_vars.yml
@@ -532,15 +532,21 @@ minetest_flat_world: False
 # Platforms - turn all off and let /opt/iiab/iiab/vars/<OS>.yml turn on as appropriate
 
 # Wide to narrow (insofar as poss)
-is_debuntu: False
+is_debuntu: False    # covers all 3: Ubuntu, Debian, Raspbian
+
 is_ubuntu: False
+is_ubuntu_19: False
 is_ubuntu_18: False
 is_ubuntu_17: False
 is_ubuntu_16: False
-is_debian: False
+
+is_debian: False    # covers both: Debian, Raspbian
 is_debian_10: False
 is_debian_9: False
 is_debian_8: False
+
+is_raspbian: False    # covers RPi HW and non-RPi HW versions of Raspbian
+is_raspbian_10: False
 is_raspbian_9: False
 is_raspbian_8: False
 is_rpi: False