is-incognito-mode - v2.3.0
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    Variable DEFAULT_PRIVATE_QUOTA_BYTESConst

    DEFAULT_PRIVATE_QUOTA_BYTES: number = ...

    Default cutoff (9.5 GiB) for the Chromium storage-headroom strategy.

    Chrome's predictable-reported-quota mitigation (default since Chromium 147) reports navigator.storage.estimate() quota as usage + 10 GiB in a normal tab but usage + 9 GiB in an incognito tab. The headroomquota - usage — is therefore a stable 10 GiB vs 9 GiB. 9.5 GiB is the midpoint: below it means incognito, above it means normal.

    Older Chromium (< 147) reported a small dynamic quota in incognito and a disk-bound quota (tens-to-hundreds of GiB) in a normal tab, so the same 9.5 GiB cutoff classifies those correctly too.