How to make Chrome use Deluge for magnet links in Fedora
The three things you need to know:
1) Unlike Firefox, Chrome uses xdg-open to choose the default program to open a file.
2) You can set the default application for each type by using xdg-mime.
3) The Fedora desktop file for Deluge is fedora-deluge.desktop and not deluge.desktop.
xdg-mime default fedora-deluge.desktop x-scheme-handler/magnet