Going from ArcMap to ArcGIS Pro, I am very disappointed that the contents pane can't see .arpx project files. It seems to defy all logic not to have that feature in the newer program.
Add the capability to list .aprx files in the Catalog Pane. Allow them to be opened from there, as you can in ArcMap.
With Pro continually 'remembering' a folder you accessed millennia ago when you want to open/save a project it would be more efficient to have favourite folders from where it is quick to get to relevant project (.aprx) files.
My scenario is that I want to open old projects in a separate instance of Pro, while working on a current job, to get symbology, titles, label formulae, etc. Using the 'Open' process means Pro keep remembering the 'wrong' place (excluding the random locations it seems to find at a whim, on a Friday) when I try to save or open things from the main instance I'm doing the job in.
A further option would be to allow an .aprx to be dragged from Windows Explorer into an instance of Pro and have it open - as with ArcMap & a .mxd
Sometimes it would be super helpfull to see ArcGIS Pro projects in catalog pane.
There is another well known open Source GIS Software where it is possible to see the own project files in its "catalog". Furthermore you can even expand these projects and see which layers are in the project. And even furtherfurthermore you can expand the layers and see the fields in the layers in the project.
And another cool thing. You even can open the project from the catalog pane. I am not sure, but I think it was possible with arcmap, too.
