diff --git a/soupsieve/util.py b/soupsieve/util.py
index 9865b115..f2a82847 100644
--- a/soupsieve/util.py
+++ b/soupsieve/util.py
@@ -9,7 +9,6 @@
 HTML = 0x2
 XHTML = 0x4
 XML = 0x8
-EXTRA = 0x10
 
 MODE_MSK = 0xF
 DEFAULT_MODE = HTML5