runmirrors.mirror - Downstream mirror list for runmirrors
ftpsync is part of the ftpsync suite for mirroring Debian and Debian-like repositories of packages. As there are way too many mirrors of Debian to populate them all from the machine that generates the archive (“ftp-master”), mirrors are organized in a tree-shaped hierarchy. Thus, every mirror has exactly one upstream from which it syncs, and each mirror can have any number of downstreams which in turn sync from it.
Debian mirror team.