@bstar_ ,
SSIS has two environments:
- Development environment, on a dev. workstation with Visual Studio and SSDT.
- Run-Time environment, on a server with SQL Server instance and SSISDB Catalog.
That Project.Params file is not used by the SSIS run-time environment.
It is just for VS during development time, and deployment phase of a SSIS Project to a server. After deployment is over, all parameters are housed in the SSISDB database. No files after that.