The STP files in the project repository root contains CS-RCS project definitions and intermediate data. These files should not be altered in any way. The critical files have a CPB file that is used as a backup to the STP file. To recover from unwanted changes, rename the CPB file to STP, or restore it from your latest backup.
The MST files are intermediate files used to optimize milestone operations. If removed, these files will be re-generated by CS-RCS.
The files ending with ",v" are GNU RCS files that hold the revision history of every file added to the RCS.