Hi,
Wouldn't that be the .ip file generated for each ip (and/or .qsys depending on your project)?
I typically only version control those files (and no ip output product), so whenever the workspace is rebuilt, it is done starting with .ip/.qsys.
The compilation of the project is scripted, so I guess it corresponds to what you are trying to do (the script is not mine, so I do not know the details).
From the .ip/.qsys, I also know you can modify parameters from scripts.
However, the project is originally designed using the GUI.
The command to add IP/QSYS files is : "set_global_assignment -name IP_FILE <path_to_ip>.ip" (resp. qsys)
Hope that helps