Variable paging of named variables

The specification doesn't say how the start and count arguments to the variables query are supposed to interact with the filter argument:

• With indexed filter, it's more-or-less obvious.
• With named filter, not so much. Does filtering apply in this case at all?
• Without a filter, it's even more underspecified. If paging applies to named variables, then how are variables supposed to be counted in case there are both? Should it essentially behave like there's one long list of both kinds of variables (but which of them come first then)? Or can they be arbitrarily interleaved?

Start by reading the variables query specification and the definitions of its filter, start, and count arguments. Compare the indexed and named cases, including requests without a filter, and document one unambiguous paging rule covering mixed variable kinds. Done means the specification answers each interaction raised in the issue.