Question: I'm currently developing a firefox extension. I use `dump()` function. But the messages are not showing up in the console. I've cahnged the value of `browser.dom.window.dump.enabled` to `true` in `about:config` and restarted firefox from command linelike `firefox.exe -console`. Still i cant see the `dump()` message. What is possibly wrong?

Btw, Is there any addon which can show the `dump()` messages without having to restart firefox in command line `firefox -console`?

Answer: 
I find this addon to be really helpful when logging errors/messages to the console: <https://addons.mozilla.org/en-US/firefox/addon/console%C2%B2/>
To finally get the output from dump(), I specified dump file location by creating a preference `browser.dom.window.dump.file` and setting it in **about:config**.

I believe I had the same issue. I couldn't get dump() to print to stderr nor the console even though I had set `browser.dom.window.dump.enabled` to `true`. I'm on Ubuntu 14.04.

Source:
<https://developer.mozilla.org/en-US/docs/Mozilla/Preferences/Preference_reference/browser.dom.window.dump.file>