It's interesting this is mentioned specifically about the metadata used by this feature: fingerprinting using this feature has similarities with other cache fingerprinting (wrote a sibling comment about that).
It's not actively bad to have defense-in-depth measures at the level of the dictionary feature. But if your implementation of dictionaries using your browser's existing cache policies is a privacy problem, I'd consider changing the cache, not just the shared-dictionary implementation.
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So it seems it should not get you anything you cannot already do with cookies.
https://github.com/WICG/compression-dictionary-transport/blo...
It's interesting this is mentioned specifically about the metadata used by this feature: fingerprinting using this feature has similarities with other cache fingerprinting (wrote a sibling comment about that).
It's not actively bad to have defense-in-depth measures at the level of the dictionary feature. But if your implementation of dictionaries using your browser's existing cache policies is a privacy problem, I'd consider changing the cache, not just the shared-dictionary implementation.