Gym badges

I don’t know the details but I believe upgraded gym badges improves your chances of better items dropping from the gym pokestop.

Gym badges only increase the drops even if you do not control the gym. So far browse is +1 silver is +2 I suspect gold is +3. If you control the gym that's +1 more drop.

When doing raids on a gym your team cot rolls all you get is more useless balls which I suspect have a lower catch rate than a regular poke ball.