Firefox developer edition + KDE Plasma 5.27

firefox-dev-kde-plasma

1) Download [Firefox Developer Edition](https://www.mozilla.org/en-US/firefox/developer/)
2) Extract to `/opt` directory ie `sudo tar -xvjf firefox-115.0b4.tar.bz2 -C /opt`
3) (Optional) rename `firefox` directory to `firefox-develop`
4) Change owner to current user so it can update the latest version ie `sudo chown $USER /opt/firefox-develop
5) Create shotcut file `vim ~/.local/share/applications/firefox-dev.desktop`

```
[Desktop Entry]
Version=1.0
Name=Firefox Developer Edition
GenericName=Firefox Developer Edition
Keywords=Internet;WWW;Browser;Web;Explorer
Exec=/opt/firefox-develop/firefox-bin %u
Terminal=false
X-MultipleArgs=false
Type=Application
Icon=/opt/firefox-develop/browser/chrome/icons/default/default128.png
Categories=GNOME;GTK;Network;WebBrowser;
MimeType=text/html;text/xml;application/xhtml+xml;application/xml;application/rss+xml;application/rdf+xml;image/gif;image/jpeg;image/png;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp;x-scheme-handler/chrome;video/webm;application/x-xpinstall;
StartupNotify=true
Actions=new-window;new-private-window;
StartupWMClass=firefox-aurora

[Desktop Action new-window]
Name=Open a New Window
Exec=/opt/firefox-develop/firefox-bin -new-window
[Desktop Action new-private-window]
Name=Open a New Private Window
Exec=/opt/firefox-develop/firefox-bin -private-window
```

Source: https://askubuntu.com/a/1393438