[mrb]

Actually the "jiat0218" user part in his email address [e-mail] has a bunch of matches on Taiwanese sites:

https://char.tw/blog/post/24397301

https://forum.babyhome.com.tw/topic/167439

https://bmwcct.com.tw/forums/thread1828.html

[5kg]

I think it's just a coincidence.

- All the posts are from 2004/2006. - "jiat" can be abbreviation for many common Chinese names.

[mrb]

I agree, probably a coincidence. Just wanted to point out we can, actually, find the username online.

[bruno-miguel]

It might just be a coincidence, but the same username from that gmail account also appears to have a Proton Mail address

[Ill_Yam_689]

I think it's not a coincidence: Hans Jansen ([e-mail]) has a matching account on Proton mail too ([e-mail]). Furthermore, the Outlook account is configured as recovery e-mail for the Proton account.