The database keeps one path per content, so a copy filed under another manufacturer was on no page of its own: the Channel F BIOS sat under Arcade > FBNeo and Fairchild had no system page. Every folder holding a copy now lists it, read from the full paths by_path_suffix records, and the index counts each content once.
Platform pages matched emulators to systems by the exact id, so the RetroArch page listed none for sega-mega-drive (genesis_plus_gx says sega-megadrive), and listed every emulator of a system instead of those the platform runs. Emulator cards linked only ids a platform uses: 2,057 of 4,215 system lines had no link, now 327, the rest having no page. Ids are compared as _norm_system_id reads them, and a system only profiles name is placed by the files they file under it.
Abdessamad Derraz