RAR archive of about 7.6 MB for the Samsung Galaxy A3 (2016), model SM-A310F. The name does not state what the package holds, though repair archives of this type typically contain service schematics and component layouts. These let a technician trace power distribution, find charging and USB circuitry and identify parts near a short circuit. Unpack with WinRAR or 7-Zip and verify the model code under the battery or on the back label, as other A3 generations use entirely different boards.
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 @esquemaseletricos. 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.