There is a content blocker API that has been available for a few years on both macOS and iOS, and there are third-party ad blockers that use it. 1Blocker is a p

There is a content blocker API that has been available for a few years on both macOS and iOS, and there are third-party ad blockers that use it. 1Blocker is a popular one. The design is more performant than holding each load up on a traditional browser extension's decision, and does not permit the content blocker to track your browsing history and then upload it somewhere. It also conveniently allows Apple to get away with not providing a more flexible browser extension API while supporting the most common use case. https://webkit.org/blog/3476/content-blockers-first-look/ https://webkit.org/blog/3476/content-blockers-first-look/