Archive for the MSI MS-7459 desktop motherboard, revision 1.0, most likely holding the board schematic in a 1.4 MB RAR package. MSI prints the MS-xxxx number and revision on the PCB, usually between the expansion slots, and these should match the document before you rely on component references. A schematic for an MSI desktop board is useful for tracing the CPU VRM phases, memory power, standby 5V and 3.3V circuits, Super I/O power-on logic and the reset path when a board will not start or shuts down immediately.
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 @cidschematicandboardviewofficial. 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.