[eureka]

hawhill nailed it. Just change the C part of luakit to handle mouse click on this area (because taps are recognized by X application as ordinary click of left button).

It's not possible within Lua (if you're don't want to mess with C part beforehand, exposing click event to Lua part). Top right part of status bar is filled by label widgets, which aren't exposing click events by default.

UPD: oh, I was wrong for it not being possible. That's what I did to test the way on my computer (NOT on Kindle):

1. $ mkdir $HOME/.config/luakit
   $ cp /etc/xdg/luakit/binds.lua $HOME/.config/luakit

2. Add this to my custom binds.lua:

   window.init_funcs["handle click on status bar (except of part filled by selectable lables)"] =
     function (w)
       w.sbar.ebox:add_signal("button-release", function (v, mods, button, context)
         print(button) -- prints 1 for left click
       end)
     end

And it printed 1 to standard output every time when I clicked status bar (except the url part, which handles clicks on its own).

Also:

$ luakit --version
luakit 039e319