This reads to me like a comment that skipped a bunch of context that would add value for the non-initiated (like me).

If I'm wrong I apologise for reading too much into it but if I'm right please add context.

Jia Tan was the alias of someone that added a backdoor to xz that could be used to allow remote code execution on OpenSSH servers using the backdoored xz version.

https://en.wikipedia.org/wiki/XZ_Utils_backdoor

Nothing a quick googling of jia Tan wouldn’t fix. It was a whole thing last year.