Meaning and usage of “which datum it might announce on the notice board”

The context of the phrase:

Participants are not allowed to come late. In such case they just don’t come. When you arrive, you will find the next meeting is next Friday (which datum it might announce on the notice board or something like that).

I assume that the definition of it in this phrase means

Used as the subject of an impersonal verb

And the meaning of the phrase then becomes: “which datum might be announced on the notice board.”

Is it an irregular/spoken use or does it appear in literature?

Answer

… which piece of information it might announce on the notice board…

The antecedent to it is probably to be found in the sentence before the first one you quoted.

For example:

This is an exclusive luncheon gathering with very strict rules respecting punctuality.
Participants are not allowed to come late. In such case they just don’t come. When you arrive, you will find the next meeting is next Friday (which datum it might announce on the notice board or something like that).

luncheon gathering <- it

The pronoun it most likely refers to the entity running the meeting, or to the meeting itself qua entity.

Attribution
Source : Link , Question Author : ib11 , Answer Author : TRomano