An explanatory letter is a short and simple document that explains something or provides information. It is usually written to help someone understand a situation, clarify a misunderstanding, or provide further context on a topic. Full definition
He also included in the statement a brief explanatory letter on the entire matter. (sportseon.com)
Recently, the Federal Tax Service of Russian Federation circulated a formal explanatory letter concerning the legal status of cryptocurrencies in the country. (coinfox.info)
As stated in the explanatory letter of the National Bank of Belarus (NBB), Belarusian banks may not do the crypto operations directly. (bit-coin-news.info)