Archive labelled for the ASUS P8Z77-M micro-ATX motherboard, a 349 KB RAR with no revision or file-type detail in its name. Extract it to check what it includes; at this size a boardview is the likely content. With a layout viewer such as OpenBoardView you can find component references, follow nets between the PCH, Super I/O and power controllers, and locate test points. Since the P8Z77-M shares part of its name with other variants like the M PRO, make sure your board is exactly this model and revision.
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 @boardview. 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.