e.g. 0, 40000, 50000
from field: repeated uint32 anchor_candidates = 2;
from field: moddef.v1.DiscoveryKind kind = 1;
SunSpec model to resolve this block to
from field: uint32 model_id = 3;
from message moddef.v1.Discovery
e.g. 0, 40000, 50000