It's not an adblocker. It's a "content blocking" engine. Basically, there are two pieces to any blocker: the blacklist, and the actual execution (matching against blacklist rules, and probably executing JS to remove it).
Safari's got a native engine for the execution part. And you pass in the blacklist with declarative rules. It's the best of both worlds in that you get competing blacklists, but the actual engine is even faster than JS. And for security like you said, there aren't any shenanigans since it's literally a JSON blacklist and can't contain code.
Safari's got a native engine for the execution part. And you pass in the blacklist with declarative rules. It's the best of both worlds in that you get competing blacklists, but the actual engine is even faster than JS. And for security like you said, there aren't any shenanigans since it's literally a JSON blacklist and can't contain code.