Well, I think that blame can get you very, very far. For example, you will
see that Josh Triplett's only (surviving) contribution to test-lib.sh is a
single line saying "unset MAIL", which is too trivial to be copyrightable
(and if it was not trivial, it still would be the only way to accomplish
what it does, so it is again not copyrightable).
Ciao,
Dscho