Here are the steps you should follow to add the TOR browser icon to the favorites bar:
$ cd tor-browser/
$ lsBrowser start-tor-browser.desktop
$ ls
Browser start-tor-browser.desktop
$ ./start-tor-browser.desktop --register-appLaunching './Browser/start-tor-browser --detach --register-app'...Tor Browser has been registered as a desktop app for this user in ~/.local/share/applications/
$ ./start-tor-browser.desktop --register-app
Launching './Browser/start-tor-browser --detach --register-app'...
Tor Browser has been registered as a desktop app for this user in ~/.local/share/applications/