The document outlines the Pan-European Laboratory (PanLab) initiative, which establishes a large-scale testing and experimentation facility by federating existing and emerging testbeds to enhance interoperability testing of networks and services. It highlights the operational and legal frameworks necessary for the collaboration between testbed providers and users, focusing on resource sharing, management, and customer support. The document also emphasizes future efforts to improve management, security, and outreach to various testing communities in Europe and beyond.