RAR package of 1.28 MB covering the Gigabyte GA-8I845PE PRO motherboard, revision 1.01. The model name refers to the Intel 845PE chipset platform for Socket 478 Pentium 4 processors. The contents are not named, but such archives normally hold circuit diagrams used to find failed MOSFETs in the CPU regulator, follow the standby 5V and 3.3V rails and check the clock generator. Compare the revision on the PCB with 1.01 first, since part placement can differ between issues. Extract with WinRAR or 7-Zip.
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.