How to use nexus-maven-repository-index.gz in Nexus3?

Hi, I am trying to work on developing Jenkins UpdateCenter integrate with nexus3.
In Jenkins Update Center, it will download nexus index and list all plugins informations. Official version is not support nexus-maven-repository-index.gz of nexus3. I am trying to support it .

But now, I got some problems. I donnot know how to search infomations according nexus-maven-repository-index.gz.

I have found some docs to introduce nexus-indexer
Nexus Indexer API: Part 1
But it was ten years ago and just for Nexus2.

Anyone can provide some documents to introduce how to use nexus-maven-repository-index.gz in Nexus3 ?

The code that generates and reads Maven index files can be found here: Maven-Indexer – About


Thanks, It helps a lot to me .