Does the normal Android transfer process involve network transfers and backups, out of interest?

(it's possible that there are privacy design reasons to keep data within user control, even if it cedes some convenience)

Per the docs(https://developer.android.com/reference/android/app/backup/B...):

"The transport is for a device-to-device transfer. There is no third party or intermediate storage. The user's backup data is sent directly to another device over e.g., USB or WiFi."

Thanks!