I think public employees to the public knowing how much a particular job/role at a particular location on the salary ladder at a particular agency. But unless they share their particular role/ladder location with friends, I don't think they are opting into sharing their exact salary; only their salary range.
The people that I know who work for the federal government simply say "I'm a mathematician at NASA", not "I'm a GS-13, Step 4 mathematician and BTW, I got a bonus of X last year."
The people that I know who work for the federal government simply say "I'm a mathematician at NASA", not "I'm a GS-13, Step 4 mathematician and BTW, I got a bonus of X last year."