Hi, I have a cross platform (iOS/MacOS) app published. Now I only want to stop the distribution of the MacOS app, how do I do that?

Hi, today I saw in the App Store Connect, that I earned some money with "Ad Backfill (US)". What is this? Since I only have 2 apps in the store which are free and use Admob to generate some revenue, I'm wondering where this backfill is comming from. Any ideas?