The CoreTrustSeal+FAIRenabling Capability Maturity (CapMat) model aligns the CoreTrustSeal Requirements with the FAIR Data Principles, allowing repositories to self-assess their practice and associated evidence with a view to their development and improvement. The FAIR Data Principles define the expectation that digital objects should be findable, accessible, interoperable and re-usable. Repositories provide the organisational context for enabling FAIR data. Trustworthy digital repositories (TDR), such as those certified to the CoreTrustSeal, offer long-term digital preservation services that can ensure digital assets remain FAIR over time. This text describes the alignment between the 15 FAIR Data Principles and the 16 CoreTrustSeal Requirements so that repositories can self assess their trustworthiness and FAIR enabling status together. The associated capability-maturity model measures the repository in terms of the policies and procedures used to deliver (meta)data services. FAIR enabling, trustworthy digital repositories are acknowledged as key nodes in the research data lifecycle and in networks of federated data infrastructures, including the European Open Science Cloud (EOSC). The community development of indicators, metrics and automated systems for assessing compliance with the FAIR Data Principles is ongoing and to date, no formal standard, process and governance structure is in place to certify FAIR objects or FAIR enabling repositories. The CoreTrustSeal+FAIRenabling CapMat self-assessment can be used immediately by repositories seeking to to identify current levels of capability and to plan for increased maturity. Applying this approach supports the readiness of a repository for formal CoreTrustSeal certification. Other types of data service can also use it to prepare for future assessments of FAIR enabling capability. Development of the CoreTrustSeal+FAIRenabling CapMat model within FAIRsFAIR has benefited from a range of internal perspectives including policy administration, data services, repository support, registry developments, and guidance and testing for object FAIRness. Iterations of the model have been improved through engaged and informed public feedback. This paper presents guidance for those applying the CoreTrustSeal+FAIRenabling CapMat model and provides detailed alignment of the CoreTrustSeal Requirements, FAIR Principles and Capability-Maturity levels. Concluding remarks reflect on the next steps for FAIRenabling TDRs, trustworthy data services and FAIR certification.

DRAFT NOT YET APPROVED BY THE EUROPEAN COMMISSION. Updated to reflect the most recent changes in alignment between the FAIR Data Principles and the FAIRsFAIR Metrics in the supporting spreadsheet template.