Duowan.com

In approximately 2011, data was allegedly obtained from the Chinese gaming website known as Duowan.com and contained 2.6M accounts. Whilst there is evidence that the data is legitimate, due to the difficulty of emphatically verifying the Chinese breach it has been flagged as "unverified". The data in the breach contains email addresses, user names and plain text passwords. Read more about Chinese data breaches in Have I Been Pwned.