"Deferred" is an excellent way to put it. It's not so much that no one
will ever want to apply a schema to the data or derive a schema from
it. Rather, it's that decisions about schemas can come later, in the
field, made by people consuming or creating documents. They may not
even be formal decisions.
It's much the same as with requirements. Even if there are no formal
requirements, they exist informally in the mind of the document
writer/programmer/software engineer/... Especially when other people
are involved, it may be useful to articulate them into a set of written
requirements. But they are in there somewhere anyway.
