The libraries package was created for a reason:

Thanks for the review @per1234!

Are we using this package somewhere? I could not find any reference to it.

If it's not used I'd prefer to remove it (even if it's technically a breaking change, I'm pretty sure nobody outside Arduino is using it).

If we are using I'd like to replace it with a package in the arduino-cli as we did for the fqbn, to reduce the spreading of the implementations.

Are we using this package somewhere?

Yes, it is used here:

https://github.com/arduino/library-registry/blob/72c93c1c90b1e201b4127d24059bb614af48352c/.github/workflows/assets/validate-registry/main.go

I'd like to replace it with a package in the arduino-cli as we did for the fqbn, to reduce the spreading of the implementations.

It doesn't make sense to move it to the github.com/arduino/arduino-cli module because Arduino CLI doesn't use the registry file.

It doesn't make sense to move it to the github.com/arduino/arduino-cli module because Arduino CLI doesn't use the registry file.

I see.

What about moving validate-registry/main.go in a sub-command of libraries-repository-engine?

I think this would give us some long-term advantages:

• the GitHub workflow in library-registry that checks the registry format would need to download the latest release of the library-repository-engine and run it on the registry.txt to check it, without the need to build it as a golang project.
• it will simplify the library-registry repo since we could remove all the golang tooling assets
• it will move all the business logic in a single place, which is easier to keep in sync

What about moving validate-registry/main.go in a sub-command of libraries-repository-engine?

Sounds good.