SageMath development is now hosted on GitHub. Trac tickets correspond to issues there number by number, e.g. https://trac.sagemath.org/ticket/34770 became https://github.com/sagemath/sage/issues/34770, etc.

There is also a read-only archive of trac.sagemath.org.