Dual airspeed - estimating relative side slip

Has anyone done any dev/experimentation with dual airspeed sensors?

There is a parameter that allows a second airspeed sensor to be enabled but I can not see anywhere that actually uses the data from arspd2. Has anyone done work on this?

If I can get the arspd value visible and logging I can see value in writing a LUA script to monitor the two sensors for errors and also attempt to measure side slip.