You need to have the application curl installed. Most Linux distros will already have it included. However, you may need to run either:
$ sudo dnf -y install curl
$ sudo pacman -Syu && sudo pacman -S curl
$ sudo apt update && sudo apt install -y curl
Once curl is installed, we can use it as well as the tar application to decompress the tarball Mozilla uses to distribute Firefox. Linux makes tasks like this simple to automate, or just looking cool. With the curl application, we can combine it with tar via a pipe, we can extract the tarball "on the fly". All we have to do is to run the following command:
$ curl --location "https://download.mozilla.org/?product=firefox-devedition-latest-ssl&os=linux64&lang=en-US" | tar --extract --verbose --preserve-permissions --bzip2
Now all we need is to put things in the appropriate places and clean up. I am going to specify installing for any user with the appropriate permissions.
First we want to take our firefox directory, and put it someplace everyone can get to it:
$ sudo mkdir -p /opt
Next, we simply have to add it to the $PATH variable for everyone. One of the more standard ways of accomplishing this is to create a symbolic link or shortcut in the /usr/bin directory, which will be loaded for all users. Note: I am naming this firefox-dev so that we can still have the "normal" version of Firefox installed as well.:
$ sudo ln -s /opt/firefox/firefox /usr/bin/firefox-dev
To make it a little easier, we should also create a shortcut to launch from Gnome. Paste the following into a file called /usr/share/applications/firefox-dev.destop:
Name=Firefox Developer Edition
GenericName=Web Browser
Exec=/home/egdoc/.local/bin/firefox-dev %u
Icon=/home/egdoc/.local/opt/firefox/browser/chrome/icons/default/default128.png
Terminal=false
Type=Application
MimeType=text/html;text/xml;application/xhtml+xml;application/vnd.mozilla.xul+xml;text/mml;x-scheme-handler/http;x-scheme-handler/https;
StartupNotify=true
Categories=Network;WebBrowser;
Keywords=web;browser;internet;
Actions=new-window;new-private-window;
StartupWMClass=Firefox Developer Edition
[Desktop Action new-window]
Name=Open a New Window
Exec=/home/egdoc/.local/bin/firefox-dev %u
[Desktop Action new-private-window]
Name=Open a New Private Window
Exec=/home/egdoc/.local/bin/firefox-dev --private-window %u