In 5.0, we had a "Gather packages" leg which took RID-specific packages from all the individual legs and combined them into one tarball, along with universal packages, to create the previously-source-built tarball that was used in future builds.
A more storage-efficient and CI-friendly way of doing this would be to have one PSB tarball for universal packages, along with independent packages for each RID as needed.
In 5.0, we had a "Gather packages" leg which took RID-specific packages from all the individual legs and combined them into one tarball, along with universal packages, to create the previously-source-built tarball that was used in future builds.
A more storage-efficient and CI-friendly way of doing this would be to have one PSB tarball for universal packages, along with independent packages for each RID as needed.