Brett, I agree that it would be good if the use of this non-standard IPv6 mask is changed as well.
But I still think it makes sense to fix the sysconfig renderer in cloud-init. cloud-init already does the conversion in several renderers, for example Eni and NetPlan. It is only the sysconfig renderer that does not render functional route6-$DEV files.
Brett, I agree that it would be good if the use of this non-standard IPv6 mask is changed as well.
But I still think it makes sense to fix the sysconfig renderer in cloud-init. cloud-init already does the conversion in several renderers, for example Eni and NetPlan. It is only the sysconfig renderer that does not render functional route6-$DEV files.