Schematic of 1.29 MB in PDF format, named only M7V, with no brand, device or board revision stated. Open it in any PDF reader and identify the board from the title block before working from it. Once confirmed, the diagram lets a technician follow power rails and signal lines, check the power-on sequence and find components and test points when diagnosing a fault. Because short codes like this are reused by different makers, compare the board number on the PCB carefully.
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 .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.