pkg-query(8) variables and %R for repository

[Graham Perrin]

pkg query -e '%a = 0' '%o %R' | grep poudriere | grep -v FreeBSD| sort

– has the required result, a sorted list of non-automatic packages from 
my poudriere repository.

I'd like a simpler list – just the origins – however this finds nothing:

pkg query %o '%R = poudriere'

What's the logic for %R being a pattern for a query, but _not_ a 
variable for an evaluation?

Is there scope for an enhancement to pkg-query?