Archive for the Apple iPhone 5S, the largest in this set at 8.74 MB in RAR form, though the name gives no breakdown of its contents. It likely gathers logic board schematics and boardview data for diagnosing no-power, no-boot, Touch ID or charging faults. Technicians use the boardview to locate a component and the schematic to see which rail it sits on and what voltage to expect. Programs such as FlexBV open layouts, and check the board version against your phone before relying on it.
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.