Author of the uBlock Origin extension, Raymond Hill, told The Register that Microsoft (and Google's) claim that the changes improve privacy is false. "They are not deprecating the Web Request API, they are deprecating the blocking ability of the Web Request API – specifically, the 'webRequestBlocking' permission. The Web Request API will still be available and still be able to provide information about all network requests fired by the browser … as opposed to what those announcements state, the deprecation of the blocking ability of the webRequest API accomplishes nothing privacy-wise for content blockers since they will still require broad hosts permissions."
Hill said that other features such as run-time host permissions (RTHP) and forbidding remote code execution (RCE) are more effective for protecting privacy, but that these are not done with Manifest v3, since RTHP is a browser feature and forbidding RCE "is a store policy issue, not an API one … those Manifest v3 announcements improperly attribute virtues (RTHP and no-RCE) to Manifest v3 which are technically unrelated to Manifest v3."
Hill also quoted the EFF report, which said that "the next time Google [or Microsoft] claims that Manifest V3 will be better for user privacy and security, don’t believe their hype … Manifest V3 will curtail innovation and hurt the privacy and security of Chrome users."
Not surprising, makes investing on NextDNS and/or Pi Hole even more significant giving the devastating changes to ad blockers.Microsoft will adopt Chromium's Manifest V3 on Edge, likely killing ad blockers