What is the date today? (subject)

[Alexey86]

Usually the question's subject can be easily found in the full answer:
What is her name? -> Her name is Jane.

The full answer to What is the date today? could be either (a) Today is September 1st or (b) Today's date is September 1st.

My questions:
1) What's the question's subject, the date today or the date?
2) Is Today the real subject in (a)?
3) In (a), is Today referring to the date today or the date?

 

[Alexey86]

After some thought, the date today seems to be the subject because it functions as a whole semantic unit.
By question (2) I mean maybe there is ellipsis: Today('s date) is September 1st.

 

[jutfrank]

1) Yes, the subject is the date today.
2) No.
3) The word Today is a noun phrase here. The meaning is equivalent to the date today or today's date.

 

[Alexey86]

1) Yes, the subject is the date today.

What's the syntactic function of "what"?