Whenever two or more topic maps that are governed by the same TM Application are merged, some of their built-in nodes, such as the nodes whose subjects are the bootstrapping assertion types, will always be duplicated in every topic map, and therefore will always merge. Others, such as the built-in nodes whose SIDP values are derived from data contained in different syntactic instances, may not be duplicated, and therefore may not merge.

Should this be a note? Reason I ask is because these are the normal
merging rules but applied to predefined nodes.