What does "this" refer to? Does it refer to "that"?

"Note that" means "notice" or "be aware", the "that" there is part of the idiom.

What does "this" refer to? Does it refer to "that"?

Note that

Well, the question is What does "this" refer to?

Note that there may be incorrect spellings, punctuation and/or grammar in this document. This is to allow correct pronunciation and timing by a speech synthesiser.
More:
http://www.hawking.org.uk/the-origin-of-the-universe.html

Now we have confirmed "this = that."

oristarA wrote:

Now we have confirmed "this = that."

Incorrect.

"That" does not stand alone in the sentence. It is part of an idiom "note that".

Drop "note that" completely and then see if you understand the meaning of "this".

"Note that" means "notice" or "be aware", the "that" there is part of the idiom.

Note that

oristarA wrote:

Note that

You continue to have problems with idioms and try to split them into individual words to understand them.

Note that is an idiom.

English speakers have a wide range of accents.

Speech synthesizers can be set to have different voices and accents.

You need to enter the spellings and punctuation that give you the rhythm and accent you want. Sometimes those spellings are not correct - they reflect the argument that some of us have had with omsigdavid. He likes to use phonetic spelling - but his version of phonetic spelling only works for his particular accent.