Files generated by the Quartus® Prime Standard Edition software that are a version-compatible representation of the internal database files. You can create version-compatible database files by using quartus_cdb with the --export_database option, the Tcl command export_database, or the Export Database command (Project menu). You can also recreate internal database files from version-compatible database files by using quartus_cdb with the --import_database option, the Tcl command import_database, or the Import Database command (Project menu). The following are version-compatible database file types:
There is also a Database Information File (.db_info) that dates the database files.