There's a condition which examines how many results other condition "returned" - <iterable-filter>.
It's missing from docs.

"""
<iterable-filter size="[number]">
Encloses other condition, and evaluates to true if the number of items the enclosed condition matched equals to the `size` attribute.
Used for primarily for rules testing.
"""

Was:
<classification-exists> and <hint-exists> could have a count="..." attribute so we can specify how many of these should exist in the results.

This would be especially useful for duplication checks. See WINDUPRULE-164.