About struct format of the "db_data.cpr":
I do not know the published document on about struct format of the "db_data.cpr". On "db_data.cpr", it is analytically confirmed that data is lined up like csv obtained by using tduvpe's export csv function. If you match the csv data with the data on "db_data.cpr" by binary search, you can identify the location on "db_data.cpr".
To avoid misunderstanding; The above db_data.cpr means the file of db_data.dec after decrypting.
About decrypting "db_data.cpr":
If tdu2vpe is properly set, tdu2vpe calls tdudec and processes it internally, so you do not need to manually decode it.
Please learn about using "tdudec.exe" in the document of "tdudec.exe".
Using this makes it easier to work with "tdudec.exe". Drag and drop the cpr file and click exec to get the decrypted file.