Nokia 500 handset material, hardware type RM-750, supplied as a 1.55 MB RAR archive. This Symbian touchscreen phone was identified by Nokia using the RM code, which should match the label under the battery before using any diagrams. The name does not reveal the exact contents, but schematics or board layout sheets are typical. They help repairers trace power and charging circuits, locate parts by designator, measure at test points and diagnose shorts. Extract with WinRAR or 7-Zip and check the pages against the board.
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 @esquematicosparatodos. 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.