It's unclear to me how that would work. Is there any documentation about moving libraries to GitLab? At mw:Manual:Developing libraries it is documented that Composer libraries need to be mirrored to GitHub with a service hook to notify Packagist -- is there an equivalent of this for GitLab?

Maybe this ticket was created because there is a .pipeline/config.yaml? I think that's a mistake and I filed T357949 for removing it.

In T344745#9562214, @tstarling wrote:

It's unclear to me how that would work. Is there any documentation about moving libraries to GitLab? At mw:Manual:Developing libraries it is documented that Composer libraries need to be mirrored to GitHub with a service hook to notify Packagist -- is there an equivalent of this for GitLab?

I believe that no PHP libraries have yet moved. Happy to help Shellbox (or whomsoever) be the first.

In T344745#9563918, @Jdforrester-WMF wrote:

I believe that no PHP libraries have yet moved. Happy to help Shellbox (or whomsoever) be the first.

Let's not rush to do this. There are still active discussions about the GitLab/Gerrit future for MediaWiki related repos happening at the management/planning tier.