https://www.vice.com/en_us/article/3anq59/genshin-impact-data-breach-phone-numbers

The website for miHoYo, the developer behind phenomenally popular online video game Genshin Impact, exposed the full number of multiple players for at least several weeks.

"At the time I tried a couple of random usernames [from the Genshin Impact subreddit], and I was able to see their numbers as well," skydtlee, a Reddit user who originally flagged the issue in October, told Motherboard in an online chat.