\expandafter\ltj@@IsFontJapaneseX#1//:%
\expandafter\expandafter\expandafter
\inlist@\expandafter\tmp@item\expandafter{\kenc@list}}
-\def\ltj@@IsFontJapaneseX#1/#2/:{\edef\tmp@item{{\directlua{tex.print('#1')}}}}
+\def\ltj@@IsFontJapaneseX#1/#2/:{\edef\tmp@item{{\directlua{%
+ tex.print(luatexbase.catcodetables["latex-package"], '#1')}%
+}}}
\let\extract@afont\extract@font