>From rule 2166, "Assets" "An asset is an entity defined as such by a (a) rule, (b) authorized regulation, (c) group of rules and/or authorized regulations (but if such regulations modify a preexisting asset class defined by a rule or another title of regulations, they must be authorized specifically to do so by their parent rule), or (d) contract (hereafter its backing document)"
It is clear that a backing document is only a contract from the way the rule is written. This was clearly just added in a non-careful way, but textually, a contract is a backing document and nothing else is. Therefore, there's no recordkeepor because "The recordkeepor of a class of assets is the entity (if any) defined as such by, and bound by, its backing document.". A rule of lower power defines the Treasuror as the recordkeepor for shinies, but that must defer to this higher power rule. -- >From V.J. Rada