An unofficial digest by Professor Sean D. Murphy of George Washington University School of Law and current editor of the “Contemporary Practice of the United States Relating to International Law” section of the American Journal of International Law.
Coverage is 1999/2001 - 2002/2004, with further updates anticipated.
Usually published by academic institutions or scholarly societies of international law. Although not official "digests", these may indicate practices of states. This and other year books are avaialbe on HeinOnlines Foreign and International Database.
To get the most comprehensive listing of these, search by Call Number on the UW Catalog: kZ21