Comment by lapcat

> Safari already implements Manifest V3 (it never had anything else to block ads)

This isn't entirely accurate. Confusion on the issue abounds.

From 2010 to 2019, the safariextz format had support for webRequest BlockingResponse https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web... and indeed there was a Safari version of uBlock Origin. This was eliminated in Safari version 13.

The "newer" (2015) Safari content blocker API is similar to Chrome's declarativeNetRequest. However, Manifest V3 is far broader than just eliminating webRequest BlockingResponse, though that's what people tend to focus on. For example, there are strict limits on script execution that also cause problems for userscript extensions.

Safari web extensions (2020) will continue to support Manifest V2, albeit without webRequest BlockingResponse, which Safari web extensions never supported. Apple is in the process of adding MV3 support to Safari web extensions without deprecating MV2 (just like Firefox).

In a sense, Manifest V3 and delcarativeNetRequest are separate issues. After all, delcarativeNetRequest is also supported in Chrome MV2. Chrome took the "opportunity" to eliminate webRequest BlockingResponse in MV3. Safari took the opportunity to eliminate BlockingResponse much earlier. But MV3 could have supported BlockingResponse if Google had wanted; there's nothing inherent to MV3 that precludes the API, other than an arbitrary decision.