### Current Developments and Research in Digital Product Passports  
In [9], the authors provide an overview of the current state of DPPs, emphasizing their emerging role in the circular economy. The paper scrutinizes 76 initiatives across corporate, policy, and research sectors, categorizing them into 13 distinct criteria to assess their development and impact. Central to their findings is the observation that while DPPs are pivotal to the EU's Green Deal and Twin Transition strategy, their practical application remains limited, and there is a lack of uniformity in technological and content approaches across different sectors. The success of DPP implementation heavily relies on collaborative efforts among businesses, governments, and individuals, aiming to create an open and collaborative data ecosystem in Europe. Key initiatives contributing to this ecosystem include GAIA-X and the International Data Spaces Association (IDSA) [10]. GAIA-X, backed by the European Commission, is developing a federated data structure for the digital economy, focusing on data sovereignty, transparency, security, and interoperability. The IDSA, on the other hand, is facilitating secure and standardized data exchange, crucial for the DPP's lifecycle data management. Industry-specific solutions like Catena-X for the automotive sector and the Global Battery Alliance for sustainable battery value chains are also making significant advancements [11]. These initiatives are developing frameworks for DPPs in their respective industries, aiming to enhance traceability, sustainability, and efficiency. One of the primary uses of DPPs is to enhance the traceability of products throughout their entire lifecycle. For instance, in the automotive industry, projects like Catena-X utilize DPPs to create end-to-end data chains that track hardware and software components. This traceability helps in complying with supply chain laws, ensuring the sustainability of production processes and improving quality management through real-time data sharing. DPPs also support circular economy practices by documenting the CO2 footprint and compliance with social standards, which aids in minimizing the environmental impact of automotive manufacturing. In the electronics sector, the KEEP [12] initiative demonstrates how DPPs can be used to assign unique identifiers, such as barcodes or QR codes, to electronic products. These identifiers allow organizations and users to access and share information about a product's lifecycle, including production, distribution, purchase, repairs, and recycling. This system promotes sustainable production, increased reuse, and improved material recycling. It also provides consumers with independently verified data from certifications, facilitating the resale of products and providing estimated values, ultimately contributing to a reduction in electronic waste. DPPs are also being explored in the construction industry to promote circularity and resource efficiency. Projects like Concular [13] in Germany and the development of digital material passports for buildings demonstrate how DPPs can support the construction sector in becoming more sustainable. These passports provide detailed information about the materials used in buildings, their origins, and their potential for reuse and recycling. By making this information readily available, DPPs help property owners, consultants, and contractors make informed decisions that support the circular economy, reduce waste, and lower CO2 emissions. The fashion and textile industry, known for its complex supply chains and significant environmental impact, can also benefit from DPP technology. DPPs can track the origin, production processes, and lifecycle of garments, ensuring transparency and accountability in the supply chain. This traceability helps brands comply with sustainability standards and certifications, enhancing consumer trust [14; 15]. The pharmaceutical industry can leverage the effects of digital transformation [16] to improve the traceability and authenticity of medical products.