ZIP archive of 1.76 MB for the Gigabyte GA-H55M-UD2H motherboard, an Intel H55 board for first-generation Core processors. The name states neither revision nor contents. Given the size, it probably holds a schematic, possibly alongside boardview or BIOS files, so check after extracting. A schematic helps trace VCORE, the integrated graphics and memory rails and the power sequence on a board that will not start. Confirm the revision printed on the PCB matches before trusting component values.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.