Hey Armin, I escalated this internally and here's what they had to say:
To meet upcoming enterprise compliance requirements (like the EU Cyber Resilience Act and SLSA L3), we are separating the build pipelines. The `prime-`tags are generated by the commercial, authenticated pipeline that produces SLA-backed, indemnified artifacts for SUSE Virtualization customers. Harvester will continue to remain fully functional, open, and is not losing any existing features. We'll be publishing more details soon that dive deeper into why we are evolving our build infrastructure to support both fast-moving community releases and hardened enterprise LTS builds.