diff --git a/xml/relaxng/src/resources/patches/0007_legacy.patch b/xml/relaxng/src/resources/patches/0007_legacy.patch
new file mode 100644
index 000000000000..67946ccbfcbe
--- /dev/null
+++ b/xml/relaxng/src/resources/patches/0007_legacy.patch
@@ -0,0 +1,26 @@
+Index: xml/relaxng/src/resources/html5-schema/html5/legacy.rnc
+IDEA additional info:
+Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
+<+>UTF-8
+===================================================================
+--- html5/legacy.rnc	(revision d1fb137d55cd5a5f1b9d6228d3bd49669e148540)
++++ html5/legacy.rnc	(revision aebff73f628a2e4a9321b0530831e1e36b280397)
+@@ -142,6 +142,7 @@
+ 		element applet { applet.inner.phrasing & applet.attrs }
+ 	applet.attrs =
+ 		(	common.attrs
++		&	applet.attrs.alt?
+ 		&	applet.attrs.archive?
+ 		&	applet.attrs.code
+ 		&	applet.attrs.codebase?
+@@ -149,6 +150,10 @@
+ 		&	applet.attrs.height
+ 		&	applet.attrs.width
+ 		)
++		applet.attrs.alt =
++			attribute alt {
++				string
++			}
+ 		applet.attrs.archive =
+ 			attribute archive {
+ 				common.data.uri #FIXME *comma* separated URI list (*grumble*)