Just making things extra clear :)
diff --git a/README.md b/README.md
index ee525ad..c18b276 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,8 @@
 Eventually the parse tree API will be compatible with [dart:html][d_html], so
 the same code will work on the client and the server.
 
+(Formally known as _html5lib_.)
+
 Installation
 ------------