This domain is used to serve the hashes of the 517,238,891 real world passwords that were exposed in data breaches (Pwned Passwords).
This list is the Pwned Passwords V2 dump published by Troy Hunt on his Have I Been Pwned website on a slightly different format (while maintaining the k-Anonymity model proposed by Junade Ali), as it is used on the PwnedPasswords MediaWiki extension.