Internet Message Access Protocol - Wikipedia
https://en.wikipedia.org/wiki/Internet_Message_Access_Protocol
In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by RFC 3501.
Configuring desktop email clients - Mail. Help
https://yandex.com/support/mail/mail-clients.html
When using the IMAP protocol, the email client syncs with the server and saves the structure of folders in your mailbox. Enable IMAP protocol before configuring your email client
IMAP vs. POP3: What Is It and Which One Should You Use?
https://www.makeuseof.com/tag/pop-vs-imap/
IMAP is short for Internet Message Access Protocol, while POP translates to Post Office Protocol. Consolidate multiple email accounts and servers into one inbox. What Are the Advantages of IMAP?