svcprop(1) refers to directly-attached properties without explaining them
The svcprop(1) manual page refers several times to "directly-attached" properties:
Without the -C, -c, or -s options, svcprop accesses effective properties. The effective properties of a service are its directly attached properties. The effective properties of a service instance are the union of properties in the composed view of its running snapshot and the properties in nonpersistent property groups in the composed view of the instance's directly attached properties. See smf(5) for an explanation of property composition. If the running snapshot does not exist then the instance's directly attached properties are used instead. ... -C Uses the directly attached properties, without composition. -c For service instances, uses the composed view of their directly attached properties.
But it's not really explained what this means. For an instance, I would have thought this referred to properties on the instance rather than inherited from the service, but empirically that doesn't seem to be the case. Empirically, it seems to refer to properties that are currently set on a service or instance, rather than those that came from a snapshot. It would be nice to explain this. (Sorry if I've missed it in some other manual page, but it doesn't seem to be in smf(5) either, which is where property composition is explained.)