It's disingenuous to say that Google is targeting uBlock Origin. The Manifest V2 extension architecture is fundamentally different from V3. V2 uses always running scripts while V3 requires event driven temporary workers. Additionally V3 eliminates the obviously risky V2 features like remote code execution and direct modification of network requests.
Not surprisingly, uBlock Origin relies heavily on features in V2 to perform it's functionality. It could probably be rewritten to use V3 but it's not a simple "Hey ChatGPT, make all this code into V3 compliant code." It will require a pretty fundamental rewrite.
Google made common sense improvements to the way extension work for safety and performance. Were they sad that uBlock Origin stopped working? Probably not. But I highly doubt it factored into the need for the V3 changes.
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