The ECB published the fourth progress report on the digital euro investigation phase. The report included basic principles such as free ease of use, economic incentives for purchasers and Eurosystem's own costs. For a detailed review, see the link below.
https://www.ecb.europa.eu/paym/digital_euro/investigation/governance/shared/files/ecb.degov230713-fourth-progress-report-digital-euro-investigation-phase.en.pdf?704b0eee4c20eee4dbe4970f5091a96a