- Open https://www.mediawiki.org/w/index.php?title=Special:UserLogin in Safari 12.0 on macOS 10.14.
- Tab once (Username)
- Tab again (Password)
- Tab again (??)
- The form submit button "Log in" must be reachable by tab navigation.
- The checkbox for "Keep me logged in" must be reachable by tab navigation.
After the username and password fields, the next tab leads to the Search field. That's highly unexpected.
Tabbing again then leads to the browser address bar, which indicates there are no further destinations. And indeed, tabbing again after that starts the sequence again from the start, at the Username field.