One of the stated goal of MV3 by Google[1] was to avoid extensions with broad permissions:

> our new declarativeNetRequest API is designed to be a privacy-preserving method for extensions to block network requests without needing access to sensitive data

This MV3-based AdGuard extension still requires a broad permission to "read or modify host data" on all sites[2]:

    "host_permissions": [
      ""
    ],

So what you have now is the same required permission to "read or modify host data" as with MV2, but with a network filtering engine capabilities gated by Google (an advertising company).

We can't innovate anymore the filtering capabilities of our content blocker engines as we have been constantly doing over the years.

For a recent example, there has been discussions lately with filter list maintainers of whether uBO should support AdGuard's proposed capability of being able to support pattern-matching for `domain=` filtering option[3] (uBO supports AdGuard lists).

That sort of proposition is not possible to entertain with MV3 since only Google get to decide how the filtering engine will evolve, if at all. All content blocking issues will have to be resolved with the Google-controlled filtering engine, and left unaddressed if the solution can't be shoehorned in the declarativeNetRequest API.

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[1] https://blog.chromium.org/2020/12/manifest-v3-now-available-...

[2] https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...

[3] https://github.com/AdguardTeam/CoreLibs/issues/1550

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Edit: removed stray `[` character.