There is information in the ArcMap documentation about geoprocessing tools, etc. that only seems to exist in the ArcMap docs, not the ArcGIS Pro docs. Such as how to join using Make Query Table:
Examples of queries with the Make Query Table tool - ArcMap 10.8
Related: How to join using Make Query Table?
I think it will be important for those ArcMap docs to remain online — even if ArcMap is no longer in use in the future. It might be tempting for Esri to take those pages down, but we need them in some cases to operate ArcGIS Pro.
Yes, I’ve requested that the ArcGIS Pro Make Query Table docs be improved via the feedback button. But my experience is that most of the time, those suggestions don’t get implemented.