RAR archive for the ECS H55H-I motherboard, version 1.0A, sized 547 KB. The model indicates an Intel H55 chipset board, and the I suffix in ECS naming typically means a mini-ITX layout; the name does not describe the files inside, probably schematic pages. They are useful for tracing CPU and integrated graphics supply rails, checking standby voltages and locating shorted capacitors or MOSFETs. Extract with WinRAR or 7-Zip and check that the V1.0A revision on the board matches before using the drawings.
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.