All default/local configs are stored in PowerKeeper.apk/assets:
Base config: assets/local.config
International overlay: assets/overlay/international/local.config
Device-specific overlay (optional): assets/overlay/<device>/local.config
As for the online configs that replace the local ones, there are 4 servers: China, International, Russia, Staging*.
Right now, our ROMs use the International server (we're considering to change that to China, we're testing it this week).
The online config also depends on the device, and changes from time to time, so there is no universal configuration we can shove in.
China servers:
https://ccc.sys.miui.com/api/v1/base/profile/,
https://jupiter.sys.miui.com/api/profile/getProfile.do
International servers:
https://ccc.sys.intl.xiaomi.com/api/v1/base/profile/,
https://jupiter.intl.sys.miui.com/api/profile/getProfile.do
On Weekly ROMs (and in future Stable releases), you can switch between the servers using the secret code in the Dialer app:
*#*#76937#*#*
If you switch to China server, this will disable Xiaomi's refresh rate configs for international apps, like YouTube, which unlocks the refresh rate.
Starting from next release, this will also unlock Performance mode in Security -> Battery (an additional patching is needed in Security app, we added it today).
* The Staging server isn't an actual server on the WWW, it's locally used by Xiaomi, so switching to it will freeze config updates, basically, due to failed connection.