Osmose/affiliates — comment on commit a65c5c6a2f43fef9ee309efdc5f6f42e66a831af
File: apps/browserid/views.py line 59
By Osmose:

They're the same assertion. Verify is called via AJAX to check if we need to bring up the registration form. We verify again here because this URL could be called directly by a malicious user, so we need to assert their identity again.

We could store the first assertion in the user's session instead of verifying over and over. Caching at the django-browserid level wouldn't completely solve this, as the cache could expire before the user submits their registration.