What is encrypted here(BAT54AFILM)?

[Giovanni4]

Hello!
From the datasheet, I could tell it was a BAT54AFILM (due to the D84 marking), but I couldn't figure out what E1 meant. Could you help me decipher this?

Thx!

[Ozone]

Usually a date code.
The datasheet admittedly does not reveal anything in this regard.

[Giovanni4]

I understood that this is a date code, but how can it be deciphered?