mozilla/soup — comment on commit 3f659b93dda7741aa469783c870fa1575d6f347e
File: assets/www/index.html line 15
By digitarald:

So the user can still log in when he cancelled the automatic browserid popup, or verification failed. It gets overwritten when the user is verified.

It's definitely a short term solution until we have a clear user flow defined for that (welcome message, on demand sync, account creation).