The research (PDF) Managing Access to Confidential Documents compares popular tools like ProtonMail and Gmail to prevent unauthorized data downloads.
Research on Features Analysis of All Email Components for Phishing Detection discusses how attackers lure victims into providing the credentials that eventually end up in these "MiX" lists. Defensive Best Practices Download Mail Access MiX txt
Essential for stopping hackers even if they have your password from a leaked "txt" file. The research (PDF) Managing Access to Confidential Documents