I've been trying to use links2 to view html part of messages.
The problem I'm encountering is that, the part would be saved as
/tmp/xxx/xxx.shtml and
passed on to links2, and it seems links2 doesn't recognise the .shtml
extension.

netsurf works well with .shtml though.

But being stubborn as I am, I would like to know if I can make notmuch
output .html file instead?
I did a bit of research on shtml, seems it's completely unnecessary in this
case? why would notmuch choose this extension anyway?