by Tim Hunt.
As a developer I sometimes have to pick apart .bzg files, and occasionally put them back together again after editing. And, most of the time I am stuck working on Windows.
Dealing with .tgz files there is not fundamentally harder than dealing with .zip (e.g. via wizip). If you know enough to unpack a .bgz file now, you will still be able to do it in future, I think.