Is this an official site for China?

http://sailfishos.net/

中国区业务联系人
有关中国区所有与业务相关的咨询,请联系我们:qinxuehan@126.com.

No idea how professional a 126.com email account looks in China.

That looks scammy AF, I’m sorry.

It refuses to load over https / SSL, that is (potentially) a red flag

It is owned by a GoDaddy in the US, that is (potentially) a red flag.
(sailfishos.org is owned by registrar.amazon.com)

Registrant Organization: Domains By Proxy, LLC
Registrant City: Tempe
Registrant State/Province: Arizona
Registrant Country: US

But it links to this forum and the jolla.com where i expect it to.

For example the text:

Summary

媒体/新闻联系人

请发电子邮件给我们的助手 press@sailfishos.org

deepl.com translation:

Media/Press Contacts
Please email our assistant at press@sailfishos.org