Adds an interstitial alert before visiting HTTP (insecure) sites.
This add-on will display an interstitial alert before a webpage is visited over HTTP (except if that page redirects to HTTPS).
Exceptions can be added temporarily or permanently.
Permanent exceptions can be removed in the add-on's options page.
NOTE: Requests WILL NOT be blocked immediately (they get blocked after the headers have been received), as the add-on checks if the visited page redirects to an HTTPS site.