Archived reference guide on SMD soldering, packed as a RAR of about 1.08 MB. The name indicates a general training document rather than a board-specific file, so expect technique notes on surface-mount work: flux use, iron and hot-air settings, removing and fitting small passives and fine-pitch ICs. Technicians keep such material handy when replacing MOSFETs, PWM controllers or connectors on laptop boards. Extract it with WinRAR or 7-Zip; the exact contents and file formats inside are not stated by the name.
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 @generalschematics. 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.