Hi Mattia, CRS plugins is a new feature and it will be available from version 4.0:
https://coreruleset.org/docs/concepts/plugins/#how-to-install-a-plugin "CRS 4.x will come with a plugins folder next to the rules folder." If you take a look at the existing plugins ( https://github.com/coreruleset/plugin-registry), you can see that most of them are actually part of the current stable set (3.3.x). The version 4.0 is coming soon (hope in this year), but the current version (3.3.4 in stable) is not able to handle the plugins infrastructure yet. When the 4.0 will be out, we can (must?) consider modifying the package. Regards, a.
