I think that the main issue is simply messiness if these are installed into system locations. The merge request
https://salsa.debian.org/science-team/openfoam/-/merge_requests/4 should solve these concerns.
The "dummy" library files are a useful part of the OpenFOAM build
process. They are essentially stub libraries that can act as a failsafe
for library interfaces that are unsupported or not available on the
system. Additionally, the dummy Pstream is an extremely useful MPI stub.
It obviously cannot be used for parallel calculations, but does help
solve circular linker dependencies for the gold linker, some clang
linkers and the mingw linker.
