That got a giggle out of me, but here's the likely answer. They measured the current draw of the phone in standby and divided the battery's tested rating by it:
666 days = 15984 hours 32800mAh / 15984 hours = 2.052052... mA
So assuming the phone draws only 2mA of current while in standby (I don't know enough about modern phones to know if this is plausible or not), it checks mathematically.
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That got a giggle out of me, but here's the likely answer. They measured the current draw of the phone in standby and divided the battery's tested rating by it:
666 days = 15984 hours
32800mAh / 15984 hours = 2.052052... mA
So assuming the phone draws only 2mA of current while in standby (I don't know enough about modern phones to know if this is plausible or not), it checks mathematically.