Dell N4050 archive, the first of two near-identical uploads distinguished only by the _1 suffix; both are 1.43 MB RAR files. The name does not state the board number, revision, ODM or whether the content is a schematic or boardview. Extract it with 7-Zip or WinRAR, compare it with the other copy and identify the document inside. Such material is used to trace power rails and locate components on faulty boards, but only after the board number in the file matches the one printed on your PCB.
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 @IT_SERVICE_WORLD. 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.