RAR archive of about 545 KB named only after board code MS-9623, with no brand, model or revision stated. The name says nothing about the contents, so open it to see whether it holds a schematic, a boardview or another document. Codes of this form are commonly associated with MSI boards, but nothing here confirms which product it is. Before using any data, compare the code and revision printed on the PCB. The material would normally serve for tracing power rails, finding components and checking test points.
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 @IT_SERVICE_WORLD. 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.