How does decide, where to download from?

what does Jenkins download and deployment use, to decide which download mirror to use ? (IP address ?)
I’m trying to download the generic package from a Unix machine, located in Germany. Yesterday and today, I got consistently referred to Japanese and Chinese sites (.jp / .cn)
Just when I tried again, when writing this post, I got reasonable references to .de / .be.
I’m wondering what is going on here.

The nearest geographic mirror with the file should be selected by the Jenkins mirrorbits configuration. The machine receives the URL request, checks the GeoIP location of the request, and redirects to the geographically nearest mirror with the file.

You can read more about it on:

The site provides very helpful base links that can be extended with ‘?mirrorlist’ to see the mirror status of a specific file.

Mirror statistics are available from Mirror stats