Service manual archive, judging by the SM suffix, for the Samsung GT-I9200, the Galaxy Mega 6.3. The 7.12 MB RAR most likely holds PDF pages covering schematics, component placement, exploded views and repair flowcharts. Such material helps a technician trace power, charging, LCD and RF paths, find test points and identify replacement parts. Extract it with any RAR-capable tool, and verify the model number on the device label first, as related Mega variants differ in hardware.
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 @Schematic_mobile_iran. 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.