RAR archive of 13 MB named only A10S, which most likely refers to a phone model such as the Samsung Galaxy A10s, though the name gives no brand, type of content or board revision. Open it with WinRAR or 7-Zip to find out whether it holds schematics, layouts or firmware. Such files are typically used to trace power lines, locate components or reflash a device. Because the name is so sparse, confirm the exact model code and the PCB markings on your unit match the contents before acting on anything inside.
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 @uzb4422. 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.