Firefox should suggest existing domains, when user entered wrong domain name. It should use DNS server to check each improved DNS name, so:
- User entered forums.freeciv/org
- Firefox DNS request not give any excepted result
- Firefox improved this page url and got forums.freeciv.org
- Firefox asks DNS for forums.freeciv.org and got answer: the page exist
- Firefox will display a link to forums.freeciv.org on standard domain not exists page
First extension:
6. Firefox check forum.freeciv.org in DNS
7. DNS answers that this page doesn’t exists
8. Firefox display domain not found page