What is the cite attribute for?

Question

The cite attribute specifies the address of the source of the quoted text, I think, but who uses this information?

For example:

Answer 1

Yes, the source of the quotation isn't visible to end user. So it's just a reference to the source.

Definition from WHATWG.ORG:

Content inside a q element must be quoted from another source, whose address, if it has one, may be cited in the cite attribute. The source may be fictional, as when quoting characters in a novel or screenplay.

If the cite attribute is present, it must be a valid URL potentially surrounded by spaces.