That timezone information is provided by whoever created the commits so cannot be trusted to be correct. Considering the chosen alias it's not unexpected that the timezone information was also made to look Chinese.
So could be the holiday inactivity. I'd expect multiple layers of country obfuscation as well as conflicting information to confuse you. Or none. Impossible to know for sure.
P.S. could be Taiwanese as China and Taiwan share the same timezone.
Below are links to the git mailbox files where you could see the timezone.
From 2022:
- https://github.com/tukaani-project/xz/commit/c6977e740008817...
- https://github.com/tukaani-project/xz/commit/7c16e312cb2f40b...
From 2024:
- https://github.com/tukaani-project/xz/commit/af071ef7702debe...
- https://github.com/tukaani-project/xz/commit/a4f2e20d8466369...