Small RAR archive for the Lenovo board NM-A251, labelled TOP, most likely images or layout data for the top side of the PCB. NM-xxxx is the numbering pattern used by LCFC, the Lenovo board maker. A top-side reference helps locate components, connectors and test points, and compare a damaged board with a good one. The bottom side is in a separate archive. Confirm the board number on the PCB matches, since NM-A251 and NM-A252 variants differ in parts.
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 @vinafix_bios. 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.
7-ZipWinRARThe Unarchiver (macOS)