v144 · miscellaneous

Predictable reported storage quota

Report a predictable storage quota from StorageManager's estimate API for sites that do not have unlimited storage permissions.

concepts

  1. Quota Stabilizer

    navigator.storage.estimate() now returns a stable per-origin quota that doesn't drift with system disk pressure. Predictable budgeting for offline apps.

  2. Quota Stability Probe

    Sample navigator.storage.estimate() repeatedly over time — quota should hold steady in Chrome 144, where older builds drifted.

  3. Budget Planner

    Now that quota is stable, plan against it. Tune budgets for HTTP cache, IndexedDB, OPFS, and media blobs — the planner reads your real quota and tells you what fits.

  4. Storage Breakdown

    Probe each storage API, write 5 KB test data, and see how IndexedDB, Cache API, and localStorage contribute to total usage against the stable quota. Visualised as a proportional bar chart from real StorageEstimate.usageDetails.

why it shipped

This mitigates an avenue through which it is possible to detect that a user is in incognito mode.

references