Create a super-private browsing mode in which:
- Ctrl+Shift+T doesn't open the last tab, nor does it appear in the history menu
- The session is not associated in any way to other private browsing windows that may be open at the same time (e.g., you login in connect.mozilla.org in one private window, but you will still be logged out in the super-private one)
- You can set a password for your session and it locks automatically after X minutes of inactivity
- You can't allow sites to have permissions like cookies, geolocation, notifications or autoplay
- Extensions have zero access unless you explicitly enable them each time
- Downloads don't even get listed in the download pane
- Firefox doesn't ask if you want to save passwords
- When closing the window, you can choose to keep/delete the downloaded files and created bookmarks from this session