When offering to save a new login, the username and password are sometimes not the expected values. This can happen in a few situations:
- When changing a password, the username might not be on the screen
- If there are many input fields on a page, we might pull from the wrong ones
- The password is munged before submission, and we use the more recent (munged) value
- If input fields are improperly labeled, we might trust the
autocomplete label and ignore the field
This meta bug covers general improvements to the save/update login doorhanger to cover these and similar cases.