Can not make it working on Firefox.
However, the stackexchange (my profile) shows the app installed under the "apps tab"
However, there is still no " profile page at the top: click self-destruct access-token".
When checking the app link:
The SENotifier leads to http://hewgill.com/senotifier and it works.
The Comment Self destruct leads to: http://stackapps.com/https://stackapps.com/ ?? this might be the problem!
UPDATE:
After you fixed it for the Firefox it now works and shows up...Great job.