ParaView can different open a file with *.foam extension.
Yes ?
ParaView knows how to do with it.
Yes.
ParaView know how to open a file with *.pvsm extension.
Yes and no. A .pvsm file is a state file that describe a full pipeline. It is not open by a reader but by the state loader. As you can see, File → Open and File → LoadState is not the same thing.
ParaView can open it with many filters.
No. A .pvsm is opened by the state loaded.
it is not possible, now, to show /PATH/TO/*.pvsm as the function:
If you refer to the OpenFOAM property. It is not possible and never will be.
Could you give me some reference to it?
https://kitware.github.io/paraview-docs/latest/cxx/classvtkSMStateLoader.html