RAR archive of about 1.37 MB labelled only with the phone model OPPO A83; the name does not say whether it holds a schematic, a boardview, a flash file or something else. Given the small size it is unlikely to be a full stock firmware, so it is more probably service documentation or a partial dump. Open it with 7-Zip or WinRAR and inspect the contents before planning a repair around it. If it turns out to be a firmware image, back up the device first and confirm the exact model and hardware variant match before flashing anything.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.