diff --git a/vcl/README.vars b/vcl/README.vars
index b170bb22c027..0530195363d8 100644
--- a/vcl/README.vars
+++ b/vcl/README.vars
@@ -10,6 +10,9 @@ SAL_FORCE_HC - force high-contrast mode
 
 SAL_NO_FONT_LOOKUP - disable font search and fallback and always use a hard-coded font name (for some unit tests)
 
+LO_COLLECT_UIINFO - enable the uitesting logging, value is expected to be a relative file name that
+will be used to write the log under instdir/uitest/.
+
 VCL_DOUBLEBUFFERING_AVOID_PAINT - don't paint the buffer, useful to see where we do direct painting
 VCL_DOUBLEBUFFERING_FORCE_ENABLE - enable double buffered painting
 VCL_DOUBLEBUFFERING_ENABLE - enable a safe subset of double buffered painting (currently in Writer, not in any other applications)