If you're thinking, 'Boy, to finish this I'm gonna need a cup of coffee, but those Git people will surely appreciate my finishing all 65 questions', stop right there.
"Your session has expired because you were inactive for more than an hour. You may return to your account."
This supposedly got corrected. Session cookie expiration is now 3 hours, and page uses JavaScript to keep cookie fresh, so it shouldn't timeout if you keep it open.
And you can always submit it, and go back to it later to fill the rest.
"Your session has expired because you were inactive for more than an hour. You may return to your account."