diff --git a/dev/debugging.rst b/dev/debugging.rst
index 9876d098c..0e4afd8d9 100644
--- a/dev/debugging.rst
+++ b/dev/debugging.rst
@@ -91,7 +91,7 @@ STGUIASSETS
 ~~~~~~~~~~~
 
 Directory to load GUI assets from. Overrides compiled in assets. Useful
-for developing webgui, commonly use ``STGUIASSETS=gui bin/syncthing``
+for developing webgui, commonly use ``STGUIASSETS=gui/default bin/syncthing`` (for theme *default*)
 
 STCPUPROFILE
 ~~~~~~~~~~~~