Revit doesn't differentiate between grid north and true north

Setting the angle to true north on the project base point seems to export it both in the xaxisabscissa/xaxisordinate of the map conversion (i.e. grid north rotation) as well as in the true north rotation. How do I control grid north independently from true north? How do I set the true north?

Grid north and true north are not the same. This has been incorrectly named in Revit for a long time unfortunately.

Start by reproducing the Revit IFC export with different project base point angles and inspect the map conversion xaxisabscissa/xaxisordinate alongside the true north rotation. Done should mean grid north and true north can be controlled independently and the exported values distinguish them correctly.

Written by the indexing model from the issue text.