Known issues when migrating to Manifest V3

This page lists major known issues that affect developers as they migrate to Manifest V3. Known issues are divided into two primary groups:

• Capabilities – Features that we plan to add to Manifest V3 to facilitate migration efforts.
• Bugs – Significant issues with Manifest V3 platform features that are not working as expected.

These lists are a curated subset of items from the Chromium issue tracker. For a complete list of issues, visit the issue tracker and search for items tagged with the Platform>Extensions component.

When a capability is added to the platform or a bug is addressed, it will be removed from this page at roughly the same time the change lands in Chrome's Stable channel. See What's New in Chrome Extensions for a list of recent updates.

# Capabilities

This section lists major features that will be added to the Manifest V3 platform in order to aid developers migrating from Manifest V2. Timelines included here are best effort estimates, not hard commitments.

# FIXED: webRequest.onAuthRequired events

Summary: User-installed Manifest V3 extensions could not intercept webRequest.onAuthRequired events because the webRequestBlocking permission is restricted to policy-installed extensions. Chrome now allows extensions with the webRequest and webRequestAuthProvider permissions to asynchronously supply credentials for onAuthRequired events.

Shipped in Chrome 108.

# FIXED: Offscreen Documents API

Summary: Offscreen documents are a new capability that allows Manifest V3 extensions to create a headless page (no user visible window) to call DOM APIs that aren't supported in extension service workers. Extensions can use offscreen documents to interact with the clipboard, play audio, parse HTML, and XML documents, and so on. We will continue iterating this API in future Chrome versions.

Shipped in Chrome 110.

# FIXED: Relax the fixed maximum lifetime for extension service workers

Summary: Extension service workers are currently terminated a set amount of time after starting. This fixed limit will be replaced by an activity-based system. As a result, an extension's service worker will be able to stay alive so long as it is continuously working.

Shipped in Chrome 110.

# Userscript managers support

Summary: Userscript managers cannot inject scripts that are not included in the extension's package due to platform and policy changes that prevent arbitrary code execution. To address this, the Manifest V3 platform will be expanded to specifically support user-authored scripts and styles.

Estimated timeline: Targeting Canary support in the first quarter of 2023.

# Increased quota for session storage in the Storage API

Summary: When it was introduced, the session storage area had an intentionally conservative maximum quota of 1 MB. We are planning to increase this limit, but have not yet settled on a new value.

Estimated timeline: Targeting Canary support in the first quarter of 2023.

# Bugs

# FIXED: Service workers are not started in response to webRequest events

Summary: Previously, Manifest V3 extensions only received Web Request API events for a short time immediately after installation. After the extension service worker stopped for the first time, events on this API would no longer be dispatched as intended. This effectively prevented Manifest V3 extensions from observing network requests. This issue has been resolved.

Shipped Chrome 107.

# FIXED: Sandboxed page CSP can't be customized

Summary: Declaring a custom sandboxed page content security policy in the extension's manifest.json does not override the default content security policy. This prevents extensions from integrating with services that require their scripts or iframes to be remotely loaded.

Shipped in Chrome 110.

Tracking issue: 1247690