Archive for the OPPO A71, a 1.52 MB RAR whose name carries nothing beyond the model, so the type of content is unknown until extracted. It may hold a schematic, a component layout or a small firmware piece; open it with WinRAR or 7-Zip to find out. Repair documentation of this kind helps trace power and signal lines or locate parts on the mainboard. If it proves to be firmware, back up the phone first and verify the exact model and board revision, as OPPO units are often sold in several regional variants.
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.