diff --git a/HACKING b/HACKING
index 95e86cb..5b2709d 100644
--- a/HACKING
+++ b/HACKING
@@ -69,6 +69,10 @@ CRT connected to a BBC Microcomputer.  The original photo is at
 .htaccess - Configuration for the Apache HTTP Server to make the Web
 site work properly.
 
+webstead.xhtml - An interactive editor written in JavaScript, which
+wraps around the main "bedstead" program compiled to WebAssembly.  Not
+part of the live Web site for legal reasons.
+
 Other files in the Git repository
 ---------------------------------