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We will start treating all AppCache manifests as if they contain "*" in their NETWORK section. This effectively means that we will always fallback to the network if a resource is not otherwise specified in the AppCache manifest.


There are security issues with letting websites block access to (potentially cross-origin) URLs, as this can be used to learn something about cross-origin redirects. Since AppCache is already deprecated and slated to be removed, rather than trying to fix the security aspects of this, we decided to disable the entire feature that allows blocking access to certain URLs instead.

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • No signal
  • No signal
  • No signals


Last updated on 2021-04-10