The Naz.API dataset is a massive collection of 1 billion credentials compiled using credential stuffing lists and data stolen by information-stealing malware.
Credential stuffing lists are collections of login name and password pairs stolen from previous data breaches that are used to breach accounts on other sites.
Information-stealing malware attempts to steal a wide variety of data from an infected computer, including credentials saved in browsers, VPN clients, and FTP clients. This type of malware also attempts to steal SSH keys, credit cards, cookies, browsing history, and cryptocurrency wallets.
I used to use that approach, but found in the last several years more than half the web sites I use reject email addresses with “+” characters.
I even use several sites that used to take those addresses just fine now reject them. That made me wonder if some common JS package for parsing email addresses got changed.