The BIS and the Group of Central Banks (list below) published a few documents on the operation of CBDCs (Central Bank Digital Currencies) for their use in Retail Banking.

The address for the executive summary is: https://www.bis.org/publ/othp42.pdf

Bank of Canada
European Central Bank
Bank of Japan
Sveriges Riksbank
Swiss National Bank
Bank of England
Board of Governors Federal Reserve System
Bank for International Settlements

CPMI-IOSCO published a consultative report proposing guidance on the application of the Principles for financial market infrastructures (PFMI) to systemically important stablecoin arrangements (SAs), including the entities integral to such arrangements.

That paper can be found at the following address:   https://www.bis.org/cpmi/publ/d198.pdf