diff --git a/src/calibre/debug.py b/src/calibre/debug.py
index 856f85b550..e451b516cb 100644
--- a/src/calibre/debug.py
+++ b/src/calibre/debug.py
@@ -182,7 +182,10 @@ def main(args=sys.argv):
     from calibre.constants import debug
     debug()
     if len(args) > 2 and args[1] in ('-e', '--exec-file'):
-        import calibre.customize.ui as dummy # Load allplugins
+
+        # Load all plugins user defined plugins so the script can import from the
+        # calibre_plugins namespace
+        import calibre.customize.ui as dummy
         dummy
 
         sys.argv = [args[2]] + args[3:]