This report presents a comprehensive review of the key policy initiatives that have fostered transparency and transferability of learning outcomes over the past two decades (2000-20) to promote mobility and lifelong learning. It concentrates on European-level initiatives, while also considering national developments, offering an in-depth analysis of the objectives, coherence, and contribution of these initiatives. The report adopts a long-term and comprehensive perspective across education and training sectors, with a particular focus on higher education and vocational education and training (VET).