This is the read endpoint behind the rules table in HQ and behind the automatic-distribution block in the web and mobile account details screen. It is the only endpoint of the five that a plain customer calls in normal use.
Returns 200 with an array. An account with no rules returns [], not 404 — an empty array is a valid, normal answer and is also what a caller sees today when the ownership check wrongly lets them through. Ordering follows order ascending; the client renders rules in that sequence, which is also the sequence they execute in.