I was fixing a flat on the back wheel yesterday and accidentally hit a tiny lever on the brake caliper (that I admittedly never even knew was there). I only noticed it because it clicked a few times and I obviously heard the click. It’s like a ratchet style setup (and tiny) and I tried to move it back to what I imagined was the original position but it wouldn’t budge. Didn’t want to force it as it seems to only be meant to go one way. I haven’t been able to find out what this is for despite doing loads of searches online, so I’m here in the hope of some enlightenment. Can anyone help? The bike operated as normal for the rest of the ride but I’d really like to know what this thing is for and what I’ve done by changing its position.