Questions[firefox-extensions](ubuntu)

$ firefox -v
Mozilla Firefox 60.0.1

I add the firefox addon but can't connect with that.

does anybody know what needs to be installed to play videos from www.primevideo.com on chromium or firefox in Ubuntu ?

I am using firefox 28.0 on Ubuntu 13.10. Want to know what does the Unity Desktop Integration extension do in firefox. Then I can enable or disable it according to the use of it.

Firefox constantly keep moving platformHTMLBindings.xml when it upgrade.
I want to replace it to support vi key-bindings. But I cannot find it any more.

sudo find / -name platformHTMLBindings.xml -o -name toolkit.jar -o -name omni.jar

Thanks for your help.

Edit:

I finally found it. It's called omni.ja now.

This is my editing to platformHTMLBindings.xml:

  <binding id="browser">
    <handlers>
      <handler event="keypress" key=" " modifiers="shift" command="cmd_scrollPageUp" />
      <handler event="keypress" key=" " command="cmd_scrollPageDown" />

      <handler event="keypress" key="k" command="cmd_scrollLineUp" />
      <handler event="keypress" key="j" command="cmd_scrollLineDown" />
      <handler event="keypress" key="h" command="cmd_scrollLeft" />
      <handler event="keypress" key="l" command="cmd_scrollRight" />

After Editing, I restart firefox, and clear the cache.
chrome://global/content/platformHTMLBindings.xml is correct.
But the j/k/h/l shortcuts didn't work.

I have firefox version 11.0 and am running ubuntu 11.10. Firefox takes upto 850MB RAM with only six or seven tabs opened and all the tabs loaded with light weight websites only. I wonder why would a browser consume so much memory. It keeps increasing its memory consumption over time. I have 3GB RAM and most of the times firefox consumes upto 30% of my memory. How do I fix this?

EDIT:

The output of the command sudo iotop -oPa as asked by @Jippie