It's an open-source plugin manager called StudioRack:
https://github.com/studiorack

The aim of the project is to provide a free open-source way to manage plugin dependencies and their versions. It would involve the following steps:

Publish a Github release containing the plugin source along with metadata plugins.json
Tag your Github repository with studiorack-plugin so it can be discovered
Wait for the studiorack-registry to index your plugin (every 24 hours)
Check the registry feed for your plugin to appear

If you have any questions or issues, make an issue in the Github repo or join the DIscord https://discord.gg/9D94f98PxP
This project is currently in alpha and would massively be helped by early adopters to iron out bugs and guide development!!