Question about planned route vs. real flight track log

When we see any historical flights, the flight track log provides real flight trajectory. In terms of the historical flight, where can I get the initial planned route information? (At least, I am able to see the planned route in the visualization map but I want to know the lat/long information) I am guessing that it’s defined in ‘Flight data - Route’ tap and we could decode the information?

I know that the ‘Flight data - Route’ tap provides planned route information when we see upcoming flights. However, I am unsure if this is the case for historical flights as well.