This app, in order to use the "1 byte Kana Font" as the font to display the text on the "Glaeja", is an extension to perform a character code conversion of kana characters.
The format of the extension call, please refer to the help dialog that appears at the time of application start-up to reference.
Commentary detailed how to use it, please refer to the commentary entry of Tsutana blog.
http://bananawani-mc.blogspot.jp/2016/05/glaeja-ext.html