The thing is, Firefox dev edition is not available on the default system repository so if you want to install it, you have to do it manually.

Let's get right into it.

1. Open terminal

2. Download and unpack

wget "https://download.mozilla.org/?product=firefox-devedition-latest-ssl&os=linux64&lang=en-US" -O Firefox-dev.tar.bz2

sudo tar xjf Firefox-dev.tar.bz2 -C /opt/

rm -r Firefox-dev.tar.bz2

3. Install

sudo ln -s /opt/firefox/firefox /usr/local/bin/firefox-dev

4. Run

firefox-dev

Now at this point, you have installed Firefox dev on your system and you can run it with the above command but if you want to create a shortcut(which you should), then follow along.

5. Creating Shortcut

vi Firefox-dev.desktop

If you don’t know how to use vi editor :

Press “i” to enter insert mode
copy-paste the lines given below( ctrl +c / ctrl+v )

Paste these lines inside the file :

[Desktop Entry]
Name=Firefox-developer-edition
Exec=/usr/local/bin/firefox-dev
Icon=/opt/firefox/browser/chrome/icons/default/default128.png
comment=browser
Type=Application
Terminal=false
Encoding=UTF-8
Categories=Utility;

press “ESC” to move out of insert mode.
now type “:wq” and press enter key to save and exit.

Finally :

sudo cp Firefox-dev.desktop /usr/share/applications/

6. Updating

To be honest with you using Firefox Developers Edition as your default browser is kinda annoying since it asks for updates very often and you have to do it manually.

But if you wanna update it, don’t download it from the browser, just run these commands:

wget "https://download.mozilla.org/?product=firefox-devedition-latest-ssl&os=linux64&lang=en-US" -O Firefox-dev.tar.bz2

sudo tar xjf  Firefox-dev.tar.bz2 -C /opt/

7. Removing

In some case, you wanna completely remove Firefox dev from your system:

sudo rm -r /opt/firefox/

sudo rm /usr/local/bin/firefox-dev

sudo rm /usr/share/applications/Firefox-dev.desktop

rm ~/Desktop/Firefox-dev.desktop

vinayak