Repair material for the original Apple iPhone SE in a 5.05 MB RAR; the name gives no board number or file details. Such archives typically carry schematics or boardview data used to locate components, follow signals and measure diode values at test points. Open it in a PDF reader or a boardview viewer depending on what is inside. Make sure the documentation applies to your logic board version before trusting component locations or rail names.
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.
7-ZipWinRARThe Unarchiver (macOS)