[yencabulator]

You seem to assume Mullvad stores something that allows correlating a Mullvad account to a specific incoming envelope.

Or that they store something that allows correlating an IP+time to a Mullvad account.

[transpute]

Correlation is about combining metadata to incrementally narrow datasets.

When a VPN provider isn't cooperative, metadata can be sought upstream.

Mullvad deserves much credit for accepting non-digital payments, which increases the cost of deanonymization.