--- a/mozilla/thunderbird_project_branches.py
+++ b/mozilla/thunderbird_project_branches.py
@@ -1,15 +1,16 @@
 # Additional branches that start as identical (individual variables can be overriden here)
 PROJECT_BRANCHES = {
     ### PLEASE ADD NEW BRANCHES ALPHABETICALLY (twigs at the bottom, also alphabetically)
     #####  TWIGS aka RENTABLE BRANCHES
     # Booked for Thunderbird
     'cypress': {
-        # Full set of project branch defaults
+        # mozilla_dir is blank
+        'mozilla_dir': '',
     },
 }
 
 # All is the default
 ACTIVE_PROJECT_BRANCHES = PROJECT_BRANCHES.keys()
 
 # Load up project branches' local values
 for branch in PROJECT_BRANCHES.keys():