@ruychi: I'm glad that you find the plugin useful. In response to your comments:
1. The "style (class name for footnote heading) is not respected".
The style for the footnote heading is applied from the stylesheet named Footnotes.css. This stylesheet is not generated by the plugin but has to be supplied by the user. If you use the style sheet provided in the manual and you use different class names (eg for the footnote heading) then you will need to change the names of the relevant styles in your style sheet.
2. "I would also suggest ... selectable option for having footnotes built with the <aside> element."
I have implemented your suggestion in the updated version of the plugin in the first post of this thread. Clicking the
Advanced button on the main dialog and then selecting the box
Include epub 3 types? builds footnotes with the <aside> tag.