Archive for the K43L board at revision 3.1, only 110 KB in size. That small size suggests a boardview file rather than a full schematic, but the name does not state the contents, so extract it to check. Such files let a technician locate components, look up net names and find test points while diagnosing power or signal faults. A boardview usually opens in OpenBoardView or FlexBoardView. Make sure the PCB carries the same K43L 3.1 marking, since revisions can differ in component placement.
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 .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.