Apple iPhone 6 repair archive, 15.1 MB RAR, with no board number or file type given in the name. Contents are likely schematics and possibly boardview data used to trace lines, find components and diagnose faults such as touch IC failure or no power. Schematics open in any PDF reader; layouts need a dedicated boardview viewer. Verify the documents correspond to your board before relying on component designators or measured values.
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)