Service material archive for the A500H, 10.1 MB, where the SM suffix likely denotes a service manual; the model code suggests the Samsung Galaxy A5 SM-A500H, though no brand is stated. Such manuals usually include disassembly steps, exploded views, parts lists and level-3 schematics or layouts. Extract the RAR and open the documents with a PDF viewer. Check the model sticker on your phone matches A500H exactly, as regional variants of the same series can use different boards and 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 @schematicslaptop. 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.