There are several standards that specify how offsets should appear, but only Go uses Z (meaning Zero offset, aka UTC equivalent) followed by what appears to be a _positive_ number to represent a _negative_ offset...
By this logic we can expect to see a Moscow time stamp represented as HH:MM:SS+03:00 in every other program, and HH:MM:SSZ-03:00 only in Go.
It's just wrong, for no good reason.