Just stumbled upon that yesterday and gave it a try. While I could "install" uBlock Origin, it didn't seem to have any effect and the configuration page for it was completely blank. They also say "Orion even supports some extensions out of the box on iOS, but we have much more to do here" on their page, so I guess it's not there yet.

Well, the only browser on iOS if you exclude the one that’s built in.

https://developer.apple.com/documentation/safariservices/saf...

The built-in extensions support isn't enough to support uBlock Origin.

What does uBlock do that 1Blocker can’t if you enable the web extension?

uBlock has full control over the browser's network access and can run code to determine the outcome of the request.

1Blocker/AdGuard/etc use two mechanisms:

1) declarative blocking - where you can specify rules to allow/deny requests matching a certain pattern. Those rules need to be declared in advance, you can't do matching at runtime using custom code.

2) they inject a bit of JS into the page to try and tamper with malicious scripts that can't be touched by the declarative blocking. This is error-prone and potentially slow, and is not guaranteed to be bulletproof as the injected code runs with the same privileges as the malicious code. I could see potential race conditions where the malicious code manages to run and exfiltrate sensitive data before the blocking code has a chance of defusing it.

The second approach is a horrible hack that only exists because extensions no longer have full control over the browser's networking, under the excuse of "security".

Yes because there is no issue with “security” of having a third party extension intercepting all of your network request…

But the workaround of injecting scripts directly within the page doesn't solve the security problem either, while introducing its own problem of less effective ad blocking.

Apple’s web extension api is crippled.