DHCPv6-PD relay route injection - standard?

[lists.nanog at monmotha.net (Brandon Martin)]

Is there a standard that defines/recommends behavior for route injection 
of snooped DHCPv6-PD (or IA, I guess) assignments on routers running 
relay agents?  That is, snooping or otherwise examining a relayed DHCPv6 
response for a delegated prefix (or IA, if you want) and installing a 
quasi-static route toward the relevant next-hop based on the lifetime of 
the delegation.  Typical redistribution can then be used to put it in 
IGP if you want.

It seems to be a common feature - Cisco ("Relay Agent Notification" on 
IOS-XE), Juniper ("DHCPv6-PD Route injection" on JunOS), and Arista 
("ipv6 dhcp relay install routes" on EOS), and Ruckus ("Relay Agent 
Prefix Delegation Notification" on FastIron) all seem to support it.

Google has, however, failed me at finding any standard that defines or 
recommends corresponding behavior.  RFC 8415 punts on the issue:

> the server may need a protocol or other
> out-of-band communication to configure routing information for
> delegated prefixes

It would be nice to have some sort of semi-normative behavior to at 
least refer to if only to use it to prod vendors.
-- 
Brandon Martin