Nexus Repository migration hard linking

Hi. I want to migrate from Nexus 2 to 3. Or actually merge two instances. I have a Nexus 3 instance container NPM repositories and a Nexus 2 contains Maven repositories.

I perform the migration using hard linking. And it works.

However, from there I would like to know where is the hard link performed. At which level. Because, in the end, I want to delete the Nexus 2 instance. But I can’t find in the documentation what is actually hard linked.

Let’s say I have /data/nexus2/sonatype-work/nexus and /data/nexus3/sonatype-work/nexus3. What is hard linked in there?