Kostal Integration - exactly what is Energy Yield (Day)

sorry but can someone please explain me exactly what this represents? (I know that the energy yield usually depends on multiple parameters when compared to eg the nominal PV Power - inclination of the sun, clouds, etc… but in this context I dont understand)
Let me explain…

I have the Energy produced by the PV (through the sum of the PVi inputs).
I have the Energy directly fed to the home and to the battery …
etc

What exactly does the Energy Yield represents?
the total energy (day) produced minus the energy used to charge the battery? but this is also energy “produced” and so “yield”

Thanks for the help!

Luis

PS:
here is for instance what I am measuring right now - and Energy Yield is 16.5 kWh.