\def\dumplist#1{\par\noindent\leavevmode
\hbox to 0.2\hsize{\copy#1\hss}%
\vbox{\hsize=0.6\hsize\sixtt\baselineskip=7.2pt\sixgt\let\\=\relax
-\directlua{ltj.ext_show_node_list(tex.getbox(#1).head, '\\par ', tex.print)}\hrule}}
+\directlua{luatexja.ext_show_node_list(tex.getbox(#1).head, '\\par ', tex.print)}\hrule}}
%\tracingonline=1\tracingoutput=1\showboxdepth=3\showboxbreadth=100
\setbox0=\hbox{\rmlh あ$a$さ$a$か}
\dumplist0
+
+\head{その他: unhbox の連続}
+\setbox0=\hbox{\tenmin\setbox1=\hbox{)}\setbox2=\hbox{a}\unhbox1\unhbox2}
+\dumplist0
+
+\setbox3=\hbox{\tenmin\setbox1=\hbox{)}\setbox2=\hbox{a}\unhbox1\unhbox2}
+\setbox0=\hbox{\unhbox3}
+\dumplist0
+
\end