[B.A.T.M.A.N.] What is link throughput used for?

I'm not finding a document describing how link throughput is used in routing decisions but I see in 2016.1 setting this value (and the default of learning it) are described:

Throughput override Available since: batman-adv 2016.1

Defines the throughput value to be used by B.A.T.M.A.N. V when estimating the link throughput for all neighbors connected to this interface. If the value is set to 0 then batman-adv will try to estimate the throughput by itself by either querying the WiFi driver or the Ethernet interface. B.A.T.M.A.N. IV ignores the setting entirely.

cat /sys/class/net/eth0/batman_adv/throughput_override 0.0 MBit

How is this used? Where's the documentation?

Thanks.