RAR archive of about 2.84 MB named for the Apple iPhone 6S Plus, with no indication of its contents in the file name. It may contain schematics, boardview data or component layout images, so open and identify each file first. Material of this kind helps a technician find parts on the logic board, follow power rails from the PMIC, check diode-mode readings at test points and locate shorts. Boardview files require a matching viewer program. Make sure the board number in the documents corresponds to the phone being repaired.
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 @schematic_mobiles. 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.