Unity Launcher API Addon e10s от Kotelnik

This add-on is basically what Unityfox add-on once did - pass along info about download progress to KDE Plasma 5 and Unity. If you have none of these desktop environments, this add-on is not for you.

It shows overall download progress and active download counts in task bar.

IMPORTANT: Due to security restrictions of WebExtensions platform you need to place 2 files to your home folder. Place these files:
https://github.com/kotelnik/firefox-extension-unity-launcher-api-e10s/tree/master/app-side
...to folder:
~/.mozilla/native-messaging-hosts/
...and edit launcher_api_firefox_stdin.py.json so it contains proper absolute path to the python script, e.g. "/home/YOUR_USERNAME/.mozilla/native-messaging-hosts/launcher_api_firefox_stdin.py"

This add-on no longer requires libunity library to be installed because it calls dbus directly.

The code has around 150 lines (addon + app side combined) so you can quite quickly check what it really does. Interesting source code files:
- background.js
- launcher_api_firefox_stdin.py.

Arch Linux (AUR) packge: https://aur.archlinux.org/packages/firefox-extension-unity-launcher-api-e10s