Meta: export observable array attribute's backing list

Author: tabatkins

index.bs

@@ -6729,7 +6729,7 @@ Note that when ECMAScript code sets an existing index to a new value, this will
 then the [=observable array attribute/set an indexed value=] algorithm with the new value.
 
 Every [=regular attribute=] whose type is an [=observable array type=] has a
-<dfn for="observable array attribute">backing list</dfn>, which is a [=list=], initially empty.
+<dfn export for="observable array attribute">backing list</dfn>, which is a [=list=], initially empty.
 Specification authors can modify the contents of the backing list, which will automatically be
 reflected in the contents of the observable array as observed by ECMAScript code. Similarly, any
 modifications by ECMAScript code to the contents of the observable array will be reflected back into