RAR archive, 143 KB, for the TP550LD board, revision 2.0 according to the name. The content type is not stated, and the small size points to boardview data rather than a full schematic, so check after extracting. A boardview lets a technician find components and test points, follow nets across layers and narrow down shorts quickly. Before use, check that the revision printed on the motherboard reads 2.0. Component placement can change between board revisions.
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.
7-ZipWinRARThe Unarchiver (macOS)