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Extension Pulse, week of July 13: August 31 is the Chrome Web Store's MV2 funeral

Chrome Web Store yanks remaining MV2 listings on August 31. AI-agent permissions landed at W3C. The MV2 preference storage is already deleted in Chromium.

Maxim Kosterin
4 min read
A hairline rounded square whose orange watercolor fill drains off the bottom — a Manifest V2 listing leaving the store.
A hairline rounded square whose orange watercolor fill drains off the bottom — a Manifest V2 listing leaving the store.

Chrome 150 already stopped running Manifest V2 for normal installs. This week Google named the date the store stops listing it.

August 31, 2026. After that, remaining MV2 items disappear from the Chrome Web Store. Copies already on a machine can linger, but they won't get updates and they can't be reinstalled. That's from the official MV2 deprecation timeline, updated July 8.

I already counted what the runtime sunset actually stranded — not the ad blockers, the abandoned classroom tools — in what Chrome's Manifest V2 sunset actually removed. This is the last forcing function for the long tail that still has an MV2 listing up. About seven weeks from this issue. If you don't have an MV3 package in the store by then, you don't have a store presence.

The code is being deleted, not just turned off

A Chromium CL merged July 11 (8049801) removes the per-profile MV2 deprecation preference storage. It ships in Chrome 152 (stable August 25). Combined with last week's "Chrome 151 will rip out the feature flags," the sequence is now:

  1. Runtime off — Chrome 150, June 16
  2. Flags gone — Chrome 151, July 28
  3. Prefs gone — Chrome 152, August 25
  4. Store gone — August 31

There is no chrome://flags after this. There is no enterprise exception list after Chrome 151. Anyone still hoping for a secret switch should stop.

W3C spent the week on agents, OAuth, and isolation

Three proposals showed up for the July 16 WECG meeting, all needs-triage from every vendor:

  • WECG #1041 — browser-mediated permission lifecycle for AI agents acting on a user's behalf. Mozilla's pitch: agents should inherit the extension permission model (request, grant, revoke) instead of inventing a parallel one. I counted what that model looks like at catalog scale in Mozilla wants AI agents to inherit the extension permission model.
  • WECG #1038 — browser-hosted OAuth client metadata for extensions (RFC 7591). The dream is not stuffing client IDs into manifest.json by hand.
  • WECG #1039 — COOP / COEP manifest keys so extension pages can opt into cross-origin isolation (and therefore SharedArrayBuffer). Currently a Chrome-shaped island.

There's also a review request on W3C Attribution Level 1 asking WebExtensions for an API to control attribution. Comment deadline: July 29.

None of these shipped. All of them are the kind of thing that becomes next year's "wait, that's a spec now?" if you ignore the issue tracker.

Firefox 153 is still July 21

Same ESR / file-access story as last week. Chrome 151 early stable is confirmed for July 15; full stable July 28. If you test against "whatever Stable is today," you're about to be on 151 whether you planned it or not.

What I'd do this week

MV2 on Chrome: ship something MV3 to the store before August 31, even a shell, so you keep the listing and the reviews. The Manifest V3 generator is the 20-minute version. npx @extenshi/cli will tell you if the package still smells like MV2. Five scans/month free, prepaid packs past that.

If you build agentic extensions, read #1041 before the July 16 call. The permission lifecycle they pick is the one you'll be stuck implementing.

If you need SharedArrayBuffer in an extension page, #1039 is the cross-browser path. Don't keep a Chrome-only COOP hack and call it a strategy.

Sources

Methodology

Signals dated 2026-07-06 through 2026-07-13. Duplicate chrome-mv2-deprecation-prefs-removal notes across three days are one story. Chrome listing/MAU rows in the email are catalog-universe figures for platform releases, not per-bug blast radii.

This issue of Extension Pulse is compiled from vendor docs, Chromium Gerrit, WECG issues, and Extenshi catalog snapshots. We don't independently verify every upstream claim. If something here is off, tell us at [email protected].

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