RAR archive of about 4.8 MB identified only as Apple iPhone 7 material. No board number or file type is spelled out, so inspect the contents first; such archives generally contain schematics or boardview files for the logic board. They are handy for audio IC and baseband faults, tracing the charging path, checking resistance to ground on rails and finding the matching component on the layout. Make sure the board variant you are working on matches the documentation, since carrier versions can differ.
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 @cyberlanelectonik. 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.